'Ancestor' in the Bible

"Go tell Hezekiah, "This is what the LORD God of your ancestor David has to say: "I've heard your prayer and I've seen your tears; so I will add fifteen years to your life.

Your first ancestor sinned, and your mediators rebelled against me.

then you will take delight in the LORD, and he will make you ride upon the heights of the earth; and he will make you feast on the inheritance of your ancestor Jacob, your father. "Yes! The mouth of the LORD has spoken."