If you do a thing often enough, you become that thing. Pick up a basketball, practice and play, and, in time, you will become a basketball player. So, also a pianist, a writer, a welder, and, yes, a sinner. It is argued that there are no bad people, rather people do bad things; however do a bad thing often enough, it will become part of who you are. "The sin of Judah is written with a pen of iron; with a point of diamond it is engraved on the tablet of their heart, and on the horns of their altars" (Jeremiah 17:1). The heart in Jewish thought is the essence of you. Doing is becoming. Sin leaves a deep mark. Jeremiah etched with a diamond-tipped pen the sins of Judah on the stone horns of the altar, as sin itself has left its indelible mark on the hearts of the people.
Habits can be broken, but the heart requires more; "the heart is deceitful above all things, and desperately sick; who can understand it?" (Jeremiah 17:9). Jeremiah cries for a surgeon, a Savior, because more than changing habits, he is healing hearts, "Heal me, O Lord, and I shall be healed; save me, and I shall be saved" (Jeremiah 17:14). A Savior will come, one who can and will, if you let him, erase what has been written and write something new, "I will put my law within them, and I will write it on their hearts. And I will be their God, and they shall be my people" (Jeremiah 31:33). Let him create new habits in you, repetitions of righteousness that change your heart.
Holy God, lead me in Your ways; change my heart. May I desire good, may I love deeply, as You do, so that my heart will be holy and righteous. I cannot do this, I need Someone who knows me better than I know myself. I am deceived by my own heart; You designed me for better than this. Take over, God.
Teach me new things, build in me new habits, create in me a new heart, O God.