Psalm 73:11-13 And they say, How doth God know? And is there knowledge of the Most High? Behold, these are the ungodly, who prosper in the world; they increase in riches. Verily, I have cleansed my heart in vain, and washed my hands in innocence.
The atheist says there is no God; the agnostic says we can’t know if there is a God. These are the ungodly who prosper in this life. And it seems to the faithful that they get away with unbelief and ignorance of God, and get earthly riches anyway. They will end in death with nothing.
But it is not so with me: I respond by believing God, trusting His holiness and love. Therefore, I cleanse my heart and wash my hands, by confession, repentance, faith, and receiving life. God not only demands cleanliness and holiness, He also grants it by grace through faith. We acknowledge that we are answerable to God, and that God has provided the answer in Christ.
Since we are still unclean sinners, we daily cleanse our hearts and hands (thoughts and behavior) through repentance and faith. “Create in me a clean heart, O God, and renew a right spirit within me.” We get dirty walking in this world; we get cleansed believing in Jesus Christ.