I may be wrong, but I think it means that we are all equal in God’s eyes: we all are sinners, we all are in need of a Savior, He loves us all equally... That does not mean that He does not deal with us in different ways, for example the Tribulation is aimed mostly at Israel, it is the Time of Jacob’s Trouble, but the Church will already be raptured. Israel is the apple of God’s eye, His Chosen People... The Church is the bride of Christ... God’s plans and promises for Israel will be fulfilled, just as His plans for the Church will be fulfilled also. And, at the end, we’ll all be equally blessed!
No, Christianity is equally valid for the Jews and non-Jews. Christianity started from within Judaism and is not alien to it.