1.

And the king sent, and they gathered unto him all the elders of Judah and of Jerusalem.

2.

And the king went up into the house of the LORD, and all the men of Judah and all the inhabitants of Jerusalem with him, and the priests, and the prophets, and all the people, both small and great: and he read in their ears all the words of the book of the covenant which was found in the house of the LORD.

The prophets - The suggestion to regard this word an error of the pen for “Levites,” which occurs in Chronicles (marginal reference), is unnecessary. For though Zephaniah, Urijah, and Jeremiah are all that we can name as belonging to the order at the time, there is no reason to doubt that Judaea contained others whom we cannot name. “Schools of the prophets” were as common in Judah as in Israel.
He read - The present passage is strong evidence that the Jewish kings could read. The solemn reading of the Law - a practice commanded in the Law itself once in seven years Deuteronomy 31:10-13 - had been intermitted, at least for the last 75 years, from the date of the accession of Manasseh.

3.

And the king stood by a pillar, and made a covenant before the LORD, to walk after the LORD, and to keep his commandments and his testimonies and his statutes with all their heart and all their soul, to perform the words of this covenant that were written in this book. And all the people stood to the covenant.

By a pillar - Rather, “upon the pillar” (see 2 Kings 11:14, note).
Made a covenant - “The covenant.” Josiah renewed the old covenant made between God and His people in Horeb Deuteronomy 5:2, so far at least as such renewal was possible by the mere act of an individual. He bound himself by a solemn promise to the faithful performance of the entire Law.
With all their heart - “Their” rather than “his,” because the king was considered as pledging the whole nation to obedience with himself. He and they “stood to it,” i. e., “accepted it, came into the covenant.”

4.

And the king commanded Hilkiah the high priest, and the priests of the second order, and the keepers of the door, to bring forth out of the temple of the LORD all the vessels that were made for Baal, and for the grove, and for all the host of heaven: and he burned them without Jerusalem in the fields of Kidron, and carried the ashes of them unto Bethel.

5.

And he put down the idolatrous priests, whom the kings of Judah had ordained to burn incense in the high places in the cities of Judah, and in the places round about Jerusalem; them also that burned incense unto Baal, to the sun, and to the moon, and to the planets, and to all the host of heaven.

6.

And he brought out the grove from the house of the LORD, without Jerusalem, unto the brook Kidron, and burned it at the brook Kidron, and stamped it small to powder, and cast the powder thereof upon the graves of the children of the people.

7.

And he brake down the houses of the sodomites, that were by the house of the LORD, where the women wove hangings for the grove.

8.

And he brought all the priests out of the cities of Judah, and defiled the high places where the priests had burned incense, from Geba to Beer-sheba, and brake down the high places of the gates that were in the entering in of the gate of Joshua the governor of the city, which were on a man's left hand at the gate of the city.

9.

Nevertheless the priests of the high places came not up to the altar of the LORD in Jerusalem, but they did eat of the unleavened bread among their brethren.

10.

And he defiled Topheth, which is in the valley of the children of Hinnom, that no man might make his son or his daughter to pass through the fire to Molech.

11.

And he took away the horses that the kings of Judah had given to the sun, at the entering in of the house of the LORD, by the chamber of Nathan-melech the chamberlain, which was in the suburbs, and burned the chariots of the sun with fire.

12.

And the altars that were on the top of the upper chamber of Ahaz, which the kings of Judah had made, and the altars which Manasseh had made in the two courts of the house of the LORD, did the king beat down, and brake them down from thence, and cast the dust of them into the brook Kidron.

13.

And the high places that were before Jerusalem, which were on the right hand of the mount of corruption, which Solomon the king of Israel had builded for Ashtoreth the abomination of the Zidonians, and for Chemosh the abomination of the Moabites, and for Milcom the abomination of the children of Ammon, did the king defile.

14.

And he brake in pieces the images, and cut down the groves, and filled their places with the bones of men.

15.

Moreover the altar that was at Bethel, and the high place which Jeroboam the son of Nebat, who made Israel to sin, had made, both that altar and the high place he brake down, and burned the high place, and stamped it small to powder, and burned the grove.

16.

And as Josiah turned himself, he spied the sepulchres that were there in the mount, and sent, and took the bones out of the sepulchres, and burned them upon the altar, and polluted it, according to the word of the LORD which the man of God proclaimed, who proclaimed these words.

17.

Then he said, What title is that that I see? And the men of the city told him, It is the sepulchre of the man of God, which came from Judah, and proclaimed these things that thou hast done against the altar of Bethel.

18.

And he said, Let him alone; let no man move his bones. So they let his bones alone, with the bones of the prophet that came out of Samaria.

19.

And all the houses also of the high places that were in the cities of Samaria, which the kings of Israel had made to provoke the LORD to anger, Josiah took away, and did to them according to all the acts that he had done in Bethel.

20.

And he slew all the priests of the high places that were there upon the altars, and burned men's bones upon them, and returned to Jerusalem.

21.

And the king commanded all the people, saying, Keep the passover unto the LORD your God, as it is written in the book of this covenant.

See 2 Kings 23:4 note. With this verse the author returns to the narrative of what was done in Josiah’s 18th year. The need of the injunction, “as it was written in the book of this covenant,” was owing to the fact - not that Josiah had as yet held no Passover - but that the reading of the book had shown him differences between the existing practice and the letter of the Law - differences consequent upon negligence, or upon the fact that tradition had been allowed in various points to override the Law.

22.

Surely there was not holden such a passover from the days of the judges that judged Israel, nor in all the days of the kings of Israel, nor of the kings of Judah;

The details of the Passover are given by the author of Chronicles (the marginal reference). Its superiority to other Passovers seems to have consisted:
(1) in the multitudes that attended it; and
(2) in the completeness with which all the directions of the Law were observed in the celebration. Compare Nehemiah 8:17.

23.

But in the eighteenth year of king Josiah, wherein this passover was holden to the LORD in Jerusalem.

24.

Moreover the workers with familiar spirits, and the wizards, and the images, and the idols, and all the abominations that were spied in the land of Judah and in Jerusalem, did Josiah put away, that he might perform the words of the law which were written in the book that Hilkiah the priest found in the house of the LORD.

Perform - Rather, establish. Josiah saw that it was necessary, not only to put down open idolatry, but also to root out the secret practices of a similar character which were sometimes combined with the worship of Yahweh, notwithstanding that the Law forbade them (marginal references), and which probably formed, with many, practically almost the whole of their religion.

25.

And like unto him was there no king before him, that turned to the LORD with all his heart, and with all his soul, and with all his might, according to all the law of Moses; neither after him arose there any like him.

And like unto him ... - See 2 Kings 18:5 note. We must not press the letter of either passage, but regard both kings as placed among the very best of the kings of Judah.

26.

Notwithstanding the LORD turned not from the fierceness of his great wrath, wherewith his anger was kindled against Judah, because of all the provocations that Manasseh had provoked him withal.

See the marginal references. True repentance might have averted God’s anger. But the people had sunk into a condition in which a true repentance was no longer possible. Individuals, like Josiah, were sincere, but the mass of the nation, despite their formal renewal of the covenant 2 Kings 23:3, and their outward perseverance in Yahweh-worship 2 Chronicles 34:33, had feigned rather than felt repentance. The earlier chapters of Jeremiah are full at once of reproaches which he directs against the people for their insincerity, and of promises if they would repent in earnest.

27.

And the LORD said, I will remove Judah also out of my sight, as I have removed Israel, and will cast off this city Jerusalem which I have chosen, and the house of which I said, My name shall be there.

It added to the guilt of Judah that she had had the warning of her sister Israel’s example, and had failed to profit by it.

28.

Now the rest of the acts of Josiah, and all that he did, are they not written in the book of the chronicles of the kings of Judah?

Josiah lived for 13 years after the celebration of his great Passover. Of this period we know absolutely nothing, except that in the course of it he seems to have submitted himself to Nabopolassar; who, after the fall of Nineveh, was accepted as the legitimate successor of the Assyrian monarchs by all the nations of the western coast. Josiah, after perhaps a little hesitation (see Jeremiah 2:18, Jeremiah 2:36), followed the example of his neighbors, and frankly accepted the position of an Assyro-Babylonian tributary. In this state matters remained until 608 B.C., when the great events happened which are narrated in 2 Kings 23:29.

29.

In his days Pharaoh-nechoh king of Egypt went up against the king of Assyria to the river Euphrates: and king Josiah went against him; and he slew him at Megiddo, when he had seen him.

Pharaoh-Nechoh - This king is well known to us both from profane historians, and from the Egyptian monuments. He succeeded his father Psammetichus (Psamatik) in the year 610 B.C., and was king of Egypt for 16 years. He was an enlightened and enterprising monarch. The great expedition here mentioned was an attempt to detach from the newly-formed Babylonian empire the important tract of country extending from Egypt to the Euphrates at Carchemish. Calculating probably on the friendship or neutrality of most of the native powers, the Egyptian monarch, having made preparations for the space of two years, set out on his march, probably following the (usual) coast route through Philistia and Sharon, from thence intending to cross by Megiddo into the Jezreel (Esdraelon) plain.
The king of Assyria - This expression does not imply that Nineveh had not yet fallen. The Jews, accustomed to Assyrian monarchs, who held their courts alternately at Nineveh and Babylon 2 Kings 19:36; 2 Chronicles 33:11, at first regarded the change as merely dynastic, and transferred to the new king, Nabopolassar, the title which they had been accustomed to give to their former suzerains. When, later on, Nebuchadnezzar invaded their country they found that he did not call himself “King of Assyria,” but “King of Babylon,” and thenceforth that title came into use; but the annalist who wrote the life of Josiah inmediately upon his death, and whom the author of Kings copied, used, not unnaturally, the more familiar, though less correct, designation.
Josiah went against him - Josiah probably regarded himself as in duty bound to oppose the march of a hostile force through his territory to attack his suzerain. For further details see the account in Chronicles (marginal reference). On Megiddo, see Joshua 12:21 note.

30.

And his servants carried him in a chariot dead from Megiddo, and brought him to Jerusalem, and buried him in his own sepulchre. And the people of the land took Jehoahaz the son of Josiah, and anointed him, and made him king in his father's stead.

Dead - It appears from a comparison of this passage with 2 Chronicles (marginal reference) that Josiah was not actually killed in the battle.
Jehoahaz - Or Shallum (the marginal note). He may have taken the name of Jehoahaz (“the Lord possesses”) on his accession. He was not the eldest son of Josiah (see 2 Kings 23:36 note). The mention of “anointing” here favors the view that there was some irregularity in the succession (see 1 Kings 1:34 note).

31.

Jehoahaz was twenty and three years old when he began to reign; and he reigned three months in Jerusalem. And his mother's name was Hamutal, the daughter of Jeremiah of Libnah.

32.

And he did that which was evil in the sight of the LORD, according to all that his fathers had done.

33.

And Pharaoh-nechoh put him in bands at Riblah in the land of Hamath, that he might not reign in Jerusalem; and put the land to a tribute of an hundred talents of silver, and a talent of gold.

Pharaoh-Nechoh, after bringing Phoenicia and Syria under his rule, and penetrating as far as Carchemish, returned to Southern Syria, and learned what had occurred at Jerusalem in his absence. He sent orders to Jehoahaz to attend the court which he was holding at Riblah, and Jehoahaz fell into the trap Ezekiel 19:4.
Riblah still retains its name. It is situated on the Orontes, in the Coele-Syrian valley, near the point where the valley opens into a wide and fertile plain. Neco seems to have been the first to perceive its importance. Afterward Nebuchadnezzar made it his headquarters during his sieges of Jerusalem and Tyre 2 Kings 25:21; Jeremiah 39:5; Jeremiah 52:9-10, Jeremiah 52:26.

34.

And Pharaoh-nechoh made Eliakim the son of Josiah king in the room of Josiah his father, and turned his name to Jehoiakim, and took Jehoahaz away: and he came to Egypt, and died there.

In the room of Josiah his father - Not “in the room of Jehoahaz his brother;” the phrase is intended to mark the fact, that Neco did not acknowedge that Jehoahaz had ever been king.
Turned his name to Jehoiakim - Compare 2 Kings 23:30 and 2 Kings 24:17. It seems likely, from their purely Jewish character, that the new names of the Jewish kings, though formally imposed by the suzerain, were selected by the individuals themselves. The change now made consisted merely in the substitution of יהוה yehovâh for אל 'êl (“God, Yahweh, will set up”). Both names alike refer to the promise which God made to David 2 Samuel 7:12 and imply a hope that, notwithstanding the threats of the prophets, the seed of David would still be allowed to remain upon the throne.

35.

And Jehoiakim gave the silver and the gold to Pharaoh; but he taxed the land to give the money according to the commandment of Pharaoh: he exacted the silver and the gold of the people of the land, of every one according to his taxation, to give it unto Pharaoh-nechoh.

36.

Jehoiakim was twenty and five years old when he began to reign; and he reigned eleven years in Jerusalem. And his mother's name was Zebudah, the daughter of Pedaiah of Rumah.

Twenty and five years old - Jehoiakim was therefore two years older than his half-brother, Jehoahaz 2 Kings 23:31. See his character in 2 Kings 23:37; 2 Chronicles 36:8; Ezekiel 19:5-7; Jeremiah 22:13-17; Jeremiah 26:20-23, 36:

37.

And he did that which was evil in the sight of the LORD, according to all that his fathers had done.