'Ancestors' in the Bible

Do we not have one father? Has not one God created us? Why does each of us act deceitfully, each man against his own brother, to profane the covenant of our ancestors?

"Ever since the time of your ancestors, you have turned away from my decrees and haven't kept them. Return to me and I'll return to you," says the LORD of the Heavenly Armies. "But you ask, "How will we return?'