Many Christians think that there is only gospel and that everyone goes to heaven in the same way. Gospel means good news.
Gospel of the kingdom
When Jesus Christ came down on the earth during the Old Testament, He preached the gospel.
Matthew 4:23: “And Jesus went about all Galilee, teaching in their synagogues, and preaching the gospel of the kingdom, and healing all manner of sickness and all manner of disease among the people.”
There is no death, burial, and resurrection of Jesus Christ at that time. It was, therefore, impossible to preach this. The gospel of the kingdom aimed toward the Jews as Jesus went all over Galilee, Decapolis, Jerusalem, Judaea, and from beyond Jordan etc. (Matthew 4:25), and He preached at synagogues.
Jesus preached this gospel because the Jews were waiting for the kingdom as prophesied in Old Testament.
Matthew 4:17: “From that time Jesus began to preach, and to say, Repent: for the kingdom of heaven is at hand.”
This was an earthly kingdom that the Jews were looking for. The proof is that this kingdom of heaven can suffer violence and be taken by force (Matthew 11:12). That’s also why it makes sense when Jesus gave the sermon of the mount in Matthew 5; it was preparing the Jews for an earthly kingdom that God was going to establish. He had to provide them with a lot of rules, which also indicated works.
Paul’s gospel “my gospel”
This is during the church age. This is the only gospel that Christians today can get saved by.
1 Corinthians 15:1: “Moreover, brethren, I declare unto you the gospel which I preached unto you, which also ye have received, and wherein ye stand; By which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain. For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures; And that he was buried, and that he rose again the third day according to the scriptures:”
That is why Bible believers teach only one gospel, which is salvation through the blood atonement of Christ. There is no adding of baptism, or good works, or anything else.
Galatians 1:6-8: “I marvel that ye are so soon removed from him that called you into the grace of Christ unto another gospel: Which is not another; but there be some that trouble you, and would pervert the gospel of Christ. But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed.”
This gospel has eternal security. It cannot be lost, broken, or unsealed.
Ephesians 1:13-14: “In whom ye also trusted, after that ye heard the word of truth, the gospel of your salvation: in whom also after that ye believed, ye were sealed with that holy Spirit of promise, Which is the earnest of our inheritance until the redemption of the purchased possession, unto the praise of his glory.”
Paul said in Galatians 1:6-8 that if another angel preaches a gospel, that they are damned. Through dispensationalism, one can rightly divide the word of truth and see that this angel is preaching a gospel to a different group of people in a different period.
Revelation 14:6-7 :“And I saw another angel fly in the midst of heaven, having the everlasting gospel to preach unto them that dwell on the earth, and to every nation, and kindred, and tongue, and people, Saying with a loud voice, Fear God, and give glory to him; for the hour of his judgment is come: and worship him that made heaven, and earth, and the sea, and the fountains of waters.”
Nothing here has anything to do with the death, burial, and resurrection of Jesus Christ. This is a different gospel that has to do with fearing God and worshipping Him.
Gospel of armed warfare
During the tribulation, the Jews have to arm themselves to go against the antichrist.
Hebrews 3:16-19: “For some, when they had heard, did provoke: howbeit not all that came out of Egypt by Moses. But with whom was he grieved forty years? was it not with them that had sinned, whose carcases fell in the wilderness? And to whom sware he that they should not enter into his rest, but to them that believed not? So we see that they could not enter in because of unbelief.”
God kicked out many Jews in the wilderness (they were not saved) in the Old Testament because they lacked faith that God will protect them when they fight against other nations.
Hebrews 4:1-3: “Let us therefore fear, lest, a promise being left us of entering into his rest, any of you should seem to come short of it. For unto us was the gospel preached, as well as unto them: but the word preached did not profit them, not being mixed with faith in them that heard it. For we which have believed do enter into rest, as he said, As I have sworn in my wrath, if they shall enter into my rest: although the works were finished from the foundation of the world.”
Hebrews 4:11: “Let us labour therefore to enter into that rest, lest any man fall after the same example of unbelief.”
This is a different gospel which deals with works. The following was good news because the land was good. Joshua and Caleb warned the people not to rebel against God.
Numbers 14:5-9: “Then Moses and Aaron fell on their faces before all the assembly of the congregation of the children of Israel. And Joshua the son of Nun, and Caleb the son of Jephunneh, which were of them that searched the land, rent their clothes: And they spake unto all the company of the children of Israel, saying, The land, which we passed through to search it, is an exceeding good land. If the Lord delight in us, then he will bring us into this land, and give it us; a land which floweth with milk and honey. Only rebel not ye against the Lord, neither fear ye the people of the land; for they are bread for us: their defence is departed from them, and the Lord is with us: fear them not.”
Numbers 14:11-12: “And the Lord said unto Moses, How long will this people provoke me? and how long will it be ere they believe me, for all the signs which I have shewed among them? I will smite them with the pestilence, and disinherit them, and will make of thee a greater nation and mightier than they.”
God wanted the people of Israel to believe in His saving power. This matches with the following passage where the nations of the world will gather against Israel, but God will deliver His people.
Zechariah 12:1-5: “The burden of the word of the Lord for Israel, saith the Lord, which stretcheth forth the heavens, and layeth the foundation of the earth, and formeth the spirit of man within him. Behold, I will make Jerusalem a cup of trembling unto all the people round about, when they shall be in the siege both against Judah and against Jerusalem. And in that day will I make Jerusalem a burdensome stone for all people: all that burden themselves with it shall be cut in pieces, though all the people of the earth be gathered together against it. In that day, saith the Lord, I will smite every horse with astonishment, and his rider with madness: and I will open mine eyes upon the house of Judah, and will smite every horse of the people with blindness. And the governors of Judah shall say in their heart, The inhabitants of Jerusalem shall be my strength in the Lord of hosts their God. In that day will I make the governors of Judah like an hearth of fire among the wood, and like a torch of fire in a sheaf; and they shall devour all the people round about, on the right hand and on the left: and Jerusalem shall be inhabited again in her own place, even in Jerusalem. The Lord also shall save the tents of Judah first, that the glory of the house of David and the glory of the inhabitants of Jerusalem do not magnify themselves against Judah. In that day shall the Lord defend the inhabitants of Jerusalem; and he that is feeble among them at that day shall be as David; and the house of David shall be as God, as the angel of the Lord before them. And it shall come to pass in that day, that I will seek to destroy all the nations that come against Jerusalem.”
It all ties together with “God, who at sundry times and in divers manners spake in time past unto the fathers by the prophets” (Hebrews 1:1). This book is for the Jews going through tribulation where God will fight for His people and deliver them, but they will need faith and works to fight.