'Descendant' in the Bible

concerning His Son, Jesus Christ our Lord, who was a descendant of David according to the flesh

However, it is not as though God’s word has failed [coming to nothing]. For not all who are descended from Israel (Jacob) are [the true] Israel;

I ask, then, has God rejected His people? Absolutely not! For I too am an Israelite, a descendant of Abraham, from the tribe of Benjamin.