The mystery behind the Gospel! (Israel-Jews)
For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures; (1Cor 15:3)
And that he was buried, and that he rose again the third day according to the scriptures: (1Cor 15:4)
This Gospel is nothing new especially to the Jews as it is found throughout the Old Testament.
Here are some verses that will give a clear picture why God choose this 'FOOLISH' method/way to save humanity.
And I will take you to me for a people, and I will be to you a God: and ye shall know that I am the LORD your God, which bringeth you out from under the burdens of the Egyptians. (Exod 6:7) And I will bring you in unto the land, concerning the which I did swear to give it to Abraham, to Isaac, and to Jacob; and I will give it you for an heritage: I am the LORD. (Exod 6:8)
And the Egyptians shall know that I am the LORD, when I stretch forth mine hand upon Egypt, and bring out the children of Israel from among them. (Exod 7:5)
Thus saith the LORD, In this thou shalt know that I am the LORD: behold, I will smite with the rod that is in mine hand upon the waters which are in the river, and they shall be turned to blood. (Exod 7:17)
And I will sever in that day the land of Goshen, in which my people dwell, that no swarms of flies shall be there; to the end thou mayest know that I am the LORD in the midst of the earth. (Exod 8:22)
And that thou mayest tell in the ears of thy son, and of thy son's son, what things I have wrought in Egypt, and my signs which I have done among them; that ye may know how that I am the LORD. (Exod 10:2)
...there are more in the Old Testament.
Now the same pattern in the New Testament
Then said Jesus unto them, When ye have lifted up the Son of man, then shall ye know that I am he, and that I do nothing of myself; but as my Father hath taught me, I speak these things. (John 8:28)
Now I tell you before it come, that, when it is come to pass, ye may believe that I am he. (John 13:19)
And this gospel of the kingdom shall be preached in all the world for a witness unto all nations; and then shall the end come. (Matthew 24:14)