'Cleansing' in the Bible

Therefore, thus says the Lord [to Jeremiah],“If you repent [and give up this mistaken attitude of despair and self-pity], then I will restore you [to a state of inner peace]So that you may stand before Me [as My obedient representative];And if you separate the precious from the worthless [examining yourself and cleansing your heart from unwarranted doubt concerning My faithfulness],You will become My spokesman.Let the people turn to you [and learn to value My values]—But you, you must not turn to them [with regard for their idolatry and wickedness].