The gospel of salvation is context of the discussion
not all gospels concern salvation
I can agree with you in that. The issue of salvation was murky in the OT when the good news was revealed. Even Abraham received several good news but none of them pertained to salvation.
Genesis 12: Now the Lord had said unto Abram, Get thee out of thy country, and from thy kindred, and from thy father's house, unto a land that I will shew thee:
2 And I will make of thee a great nation, and I will bless thee, and make thy name great; and thou shalt be a blessing:
3 And I will bless them that bless thee, and curse him that curseth thee: and in thee shall all families of the earth be blessed.
This is conditional, Abram must move out of his present location first, and move to a place God showed him, THEN all these good news will happen to him.
Genesis 15
After these things the word of the Lord came unto Abram in a vision, saying, Fear not, Abram: I am thy shield, and thy exceeding great reward.
2 And Abram said, Lord God, what wilt thou give me, seeing I go childless, and the steward of my house is this Eliezer of Damascus?
3 And Abram said, Behold, to me thou hast given no seed: and, lo, one born in my house is mine heir.
4 And, behold, the word of the Lord came unto him, saying, This shall not be thine heir; but he that shall come forth out of thine own bowels shall be thine heir.
5 And he brought him forth abroad, and said, Look now toward heaven, and tell the stars, if thou be able to number them: and he said unto him, So shall thy seed be.
6 And he believed in the Lord; and he counted it to him for righteousness.
This is unconditional but it has nothing to do with salvation. God is promising him numerous descendants
Genesis 17
And when Abram was ninety years old and nine, the Lord appeared to Abram, and said unto him, I am the Almighty God; walk before me, and be thou perfect.
2 And I will make my covenant between me and thee, and will multiply thee exceedingly.
3 And Abram fell on his face: and God talked with him, saying,
4 As for me, behold, my covenant is with thee, and thou shalt be a father of many nations.
5 Neither shall thy name any more be called Abram, but thy name shall be Abraham; for a father of many nations have I made thee.
6 And I will make thee exceeding fruitful, and I will make nations of thee, and kings shall come out of thee.
7 And I will establish my covenant between me and thee and thy seed after thee in their generations for an everlasting covenant, to be a God unto thee, and to thy seed after thee.
8 And I will give unto thee, and to thy seed after thee, the land wherein thou art a stranger, all the land of Canaan, for an everlasting possession; and I will be their God.
9 And God said unto Abraham, Thou shalt keep my covenant therefore, thou, and thy seed after thee in their generations.
10 This is my covenant, which ye shall keep, between me and you and thy seed after thee; Every man child among you shall be circumcised.
13 He that is born in thy house, and he that is bought with thy money, must needs be circumcised: and my covenant shall be in your flesh for an everlasting covenant.
14
And the uncircumcised man child whose flesh of his foreskin is not circumcised, that soul shall be cut off from his people; he hath broken my covenant.
24 And Abraham was ninety years old and nine, when he was circumcised in the flesh of his foreskin.
25 And Ishmael his son was thirteen years old, when he was circumcised in the flesh of his foreskin.
26 In the selfsame day was Abraham circumcised, and Ishmael his son.
27 And all the men of his house, born in the house, and bought with money of the stranger, were circumcised with him.
This was conditional too, Abraham must circumcise himself and everyone else (ouch to do that at his age v24), if he does that then the good news is contained in vs 6-8 will be for him and his descendants.
So yes, there are various good news in the OT, but as you can see from the Genesis account, none of them involve salvation as we know of now.
