1.

O LORD, thou hast searched me, and known me.

Title. A Psalm. Hebrew. mizmor. App-65 .
of David = by David. The words alleged to be Chaldaisms in verses: Psalms 139:3 , Psalms 139:4 , Psalms 139:8 , Psa 3:20 , are found in the earlier books such as Leviticus 1 and 2 Samuel. There is no internal evidence of non-Davidic authorship.
LORD. Hebrew. Jehovah. App-4 .
searched = search out as for treasures or secrets.
known = seen, so as to understand.

2.

Thou knowest my downsitting and mine uprising, thou understandest my thought afar off.

downsitting . . . uprising. Figure of speech Synecdoche (of Species), App-6 , put for all movements.
thoughts inward thought. Occurs only here and in Psalms 139:17 .

3.

Thou compassest my path and my lying down, and art acquainted with all my ways.

compassest = scrutinisest.
lying down = bed.
art acquainted with = well knowest, or hast inspected.

4.

For there is not a word in my tongue, but, lo, O LORD, thou knowest it altogether.

altogether = on every side, or, the whole of it.

5.

Thou hast beset me behind and before, and laid thine hand upon me.

behind and before. Figure of speech Synecdoche (of Species), App-6 , put for every direction.

6.

Such knowledge is too wonderful for me; it is high, I cannot attain unto it.

7.

Whither shall I go from thy spirit? or whither shall I flee from thy presence?

spirit. Hebrew. ruach. App-9 .
presence. Hebrew = face. Figure of speech Anthropopatheia. App-6 .

8.

If I ascend up into heaven, thou art there: if I make my bed in hell, behold, thou art there.

hell = Sheol. See App-35 .
behold. Figure of speech Asterismos. App-6 .

9.

If I take the wings of the morning, and dwell in the uttermost parts of the sea;

wings of the morning. See note on sub-scription of Psalms 21 .

10.

Even there shall thy hand lead me, and thy right hand shall hold me.

right hand. Figure of speech Anthropopatheia. App-6 .

11.

If I say, Surely the darkness shall cover me; even the night shall be light about me.

12.

Yea, the darkness hideth not from thee; but the night shineth as the day: the darkness and the light are both alike to thee.

hideth not from = cannot be too dark for.

13.

For thou hast possessed my reins: thou hast covered me in my mother's womb.

covered = woven me together. Compare Job 10:8 , Job 10:11 .

14.

I will praise thee; for I am fearfully and wonderfully made: marvellous are thy works; and that my soul knoweth right well.

fearfully and wonderfully. Hebrew = fears and wonders. Put by Figure of speech Metonymy (of Cause), App-6 , for the feelings produced by the works.
my soul = myself. Hebrew. nephesh. App-13 .

15.

My substance was not hid from thee, when I was made in secret, and curiously wrought in the lowest parts of the earth.

substance = frame. Hebrew = bone, as in Genesis 2:21 , Genesis 2:22 .
curiously = skillfully. Hebrew = embroidered. Compare Exodus 26:1 ; Exodus 35:35 .

16.

Thine eyes did see my substance, yet being unperfect; and in thy book all my members were written, which in continuance were fashioned, when as yet there was none of them.

substance . . . unperfect = unfinished substance. Not the same word as in Psalms 139:15 . One word in Hebrew.
unperfect. Not imperfect.
Which in continuance = the days which were ordered, or in which they should be fashioned.

17.

How precious also are thy thoughts unto me, O God! how great is the sum of them!

How precious. Figure of speech Ecphonesis. App-6 . See note on 1 Samuel 3:1 .
thoughts = desires. See Psalms 139:2 .
GOD. Hebrew El. App-4 .
sum. Hebrew, plural of majesty, denoting the fullness or vastness of them.

18.

If I should count them, they are more in number than the sand: when I awake, I am still with thee.

more in number . . . sand. Figure of speech Paroemia . App-6 .

19.

Surely thou wilt slay the wicked, O God: depart from me therefore, ye bloody men.

Surely, &c. These six verses (19-24) are not an "interpolation". They are required to complete the Structure. See above.
Thou wilt slay, &c. This is Omnipotent work. Compare Job 40:9-14 .
the wicked = a lawless one. Hebrew. rasha', App-44 .
GOD. Hebrew Eloah. App-4 .
bloody = blood thirsty.
men. Hebrew. 'enosh. App-14 .

20.

For they speak against thee wickedly, and thine enemies take thy name in vain.

wickedly = rebelliously (pre-meditated).

21.

Do not I hate them, O LORD, that hate thee? and am not I grieved with those that rise up against thee?

am not I grieved with = do I not loathe.

22.

I hate them with perfect hatred: I count them mine enemies.

23.

Search me, O God, and know my heart: try me, and know my thoughts:

thoughts = distractions or cares. Not the same word as in verses: Psalms 139:2 , Psalms 139:17 .

24.

And see if there be any wicked way in me, and lead me in the way everlasting.

wicked = painful or grievous.
way. Put by Figure of speech Metonymy (of Cause), App-6 , for the grief produced by it.
way everlasting. Put by Figure of speech Metonymy (of Effect), App-6 , for the happiness which is the effect and end of everlasting life.