Here are 3 promises that changed me forever.
Deut. 30:6 "And the Lord your God will circumcise your heart, and the heart of your seed, to love the Lord your God with all your heart, and with all your soul, that you may live."
Ezek. 36:25-29; 36b "Then will I sprinkle clean water upon you, and you shall be clean: from all your filthiness, and from all your idols, will I cleanse you. A new heart also will I give you, and a new spirit will I put within you: and I will take away the stony heart out of your flesh, and I will give you a heart of flesh. And I will put my spirit within you, and cause you to walk in my statutes, and you shall keep my judgments, and do them. And you shall dwell in the land that I gave to your fathers; and ye shall be my people, and I will be your God. I will also save and deliver you from all your uncleannesses: and I will call for the corn, and will increase it, and lay no famine upon you. I the LORD have spoken it, and I will do it."
Jer. 32:39-41 "And I will give you one heart, and one way, that you may fear me for ever, for your own good, and for your children after you: And I will make an everlasting covenant with you, that I will not turn away from you, to do you good; but I will put my fear in your heart, that you shall not depart from me. Yes, I will rejoice over you to do you good, and I will plant you in this land assuredly with my whole heart and with my whole soul."