Does one have to be a direct descendant of Israel, to be considered a Jew?
I mean, Jesus had ancestors who were of Canaanite descent, and even of Moabite descent.
Remember Rahab and Ruth?
And not all who came out of Egypt, were Israel. It says that a "mixed multitude" went out with them.
What happened to those non-Israeli people? If they joined themselves to the worship of Yahweh, would they not have been assimilated into God's people?
It seems to me, from reading the Old Testament, if one joined themselves to God's people, and with all the heart and soul pursued the worship of Yahweh, then they were accepted into the people of God. They were allowed to intermarry, and thus their offspring could be considered full Jews.
That's the only way Jesus could be considered Jewish.