1. Since when is Wikipedia the inspired word of God
2. the only thing that has been superseded is the mosaic covenant, as that which was old is passing away, and God has given us a better covenant
3. salvation, in all dispensations, has been by grace through faith, no one has ever been saved eternally by the mosaic covenant, what it does is put all under sin, that all may be made a live (all being Jew and gentile)
4. The new covenant applies to all, Jew gentile male female, free slave rich poor.
5. the covenant concerning Isreal is the part of an eternal covenant made between God and Abraham, and also confirmed with Issac and Jacob (Israel) which was a one sided covenant, (I will) as apposed to a two sided covenant (you do this, and I will do that) as was the mosaic covenant,
Believing Gods promise or covenant he made with one of Abrahams sons is not duel covenant theology, because no one, I mean no one was saved by that covenant. It was not about salvation, it was about Gods plan for one nation. Which he will accomplish,
if he does not, he is a liar and can not be trusted, period