Malachi 3:6 & 7a
"'I the Lord do not change. So you, O descendants of Jacob, are not destroyed. Ever since the time of your forefathers you have turned away from my decrees and have not kept them. Return to me, and I will return to you,' says the Lord Almighty." NIV translation
God continues to speak to his people as he reminds them that he has never changed. God chose them to be His people and He keeps his promises. If God changed and did not keep His promises, they would have been completely destroyed because of the disobedience of their fathers before them. Then, God repeats his promise to them that, if they repent, He will forgive. That is the same promise that we have today in Jesus Christ.