'Seed' in the Bible

Hath not the scripture said, That Christ cometh of the seed of David, and out of the town of Bethlehem, where David was?

They answered him, We be Abraham's seed, and were never in bondage to any man: how sayest thou, Ye shall be made free?

I know that ye are Abraham's seed; but ye seek to kill me, because my word hath no place in you.