The Gentile Calling began in the book of Acts; however, their coming to salvation was spoke of in the Tenach.

On that day I will raise up the tabernacle of David, which has fallen down, and repair its damages; I will raise up its ruins and rebuild it as in the days of old. That they may posses the remnant of Edom and all the gentiles who are called by My name. (Amos 11-12)
And now the Lord says, Who formed Me from the womb to be His Servant. To bring Jacob back to Him. So that Israel is gathered to Him. (For I will be glorious in the eyes of the Lord, And My God will be My strength), Indeed He says, “It is too small a thing that You should be My Servant, To raise up the tribes of Jacob, And restore the preserved ones of Israel; I will also give you as a light to the Gentiles, That You should be My salvation to the ends of the earth.” (Isaiah 49:5-6)

The prophets of the Tenach are speaking on how The Messiah would be the one who will restore Israel. Gentiles are also part of this plan.

Behold, my servant, whom I uphold; my chosen, in whom my soul delights: I have put my Spirit upon Him; He will bring fourth justice to the Gentiles. (Isaiah 42:1)

What is the purpose of the Gentile salvation? The Jewish Emissary Sha’ul (Paul), a Benjamite, tells us as follows:
I say then, Did they [Israelites] stumble that they might fall? God forbid: but by their fall salvation is come to the Gentiles, to provoke them to jealousy. Now if their fall is the riches of the world, and their loss the riches of the Gentiles; how much more their fulness? But I speak to you that are Gentiles, I glorify my ministry; if by any means I may provoke to jealousy them that are my flesh [other Jews], and may save some of them. (Romans 11:11-14)

Gentile Salvation has come for the purpose of restoring the Jewish people, to provoke them to jealousy. Unfortunately, “Christianity” over hundreds of years have only provoked the Jewish people, rather than showing them the Love of Messiah, Yeshua. Today, Messianic Jews and Gentiles are showing the Jewish people their Messiah from the Bible, a Jewish viewpoint, and love.