We all have sinned. Just like we can purify the germs on our hands, God wants to help us discern our thoughts and purify our hearts. God gives us a power over sin and uncleanliness.

Genesis 6:5 And GOD saw that the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only evil continually.

Eze. 44:23 And they shall teach my people the difference between the holy and profane, and cause them to discern between the unclean and the clean.

Psalms 139:23  Search me, O God, and know my heart: try me, and know my thoughts:

2 Cor. 7:1 Having therefore these promises, dearly beloved, let us cleanse ourselves from all filthiness of the flesh and spirit, perfecting holiness in the fear of God.

Matthew 10:1 And when he had called unto him his twelve disciples, he gave them power against unclean spirits, to cast them out, and to heal all manner of sickness and all manner of disease.

James 4:8 Draw nigh to God, and he will draw nigh to you. Cleanse your hands, ye sinners; and purify your hearts, ye double minded.