Someone keeps telling me that the Jews are God's chosen people, FOREVER?

According to Romans chapter 11 Israel is not rejected. The same chapter indicates that because of disbelief some "branches" were broken off that Gentiles might be "grafted in".

Galatians three refers to Christians being heirs of the promise of Abraham

Galatians 3:25-29) 25 But now that faith has come, we are no longer under a [ai]tutor. 26 For you are all sons of God through faith in Christ Jesus. 27 For all of you who were baptized into Christ have clothed yourselves with Christ. 28 There is neither Jew nor Greek, there is neither slave nor free man, there is [aj]neither male nor female; for you are all one in Christ Jesus. 29 And if you [ak]belong to Christ, then you are Abraham’s [al]descendants, heirs according to promise.

Read through the covenant God made with Abraham. This covenant has never expired, even though Israel, for the most part, rejected their Messiah (for a time).

Mine does. Genesis 17:7:

And I will establish My covenant between Me and thee and thy seed after thee throughout their generations for an everlasting covenant, to be a God unto thee and to thy seed after thee.

Um, they were the original "Jehovah" follows are still are. Your bible was written based on a false prophet. Not saying the OT was anymore true than the new one.

That just may be someone's opinion.

Believe it

Don't let 'em getcha down!!