“Get yourselves a new heart and a new spirit” (Ezekiel 18:31) means leaving behind the old age of the letter, and living in the newness of the spirit. The new heart is to forsake the idols of the Gentiles, to despise dead things, and to believe in him who is “God of the living.”

–Jerome, Commentary on Ezekiel 6

Don’t take Jerome too literally in his last sentence. Rather, think of things that my be your idols and which lead to death in your life. His point, of course, is that if we want to live, we had better make the Source and Author of all life our primary focus.