Questions: Does God see you the way you might try to appear to other people? Do you live freely without trying to be something other than who you truly are on the inside?
What the sin is: Trying to manipulate and control God and others to get what we want is in essence the sin of the religious person (including Christians). Seeing the problem in others and in the church rather than in ourselves (Isa 59:2).
Empty ritual and formalism: In Isaiah 58, God exposed the emptiness of two religious rituals that were practiced in Isaiah's day: fasting (58:3-6) and Sabbath keeping (58:13-14). Both of these are expressions of not doing things. In fasting, you don't eat. In Sabbath keeping, you don't work. Isaiah shows us that what we don't do isn't enough to make us right before God. Our walk with God shouldn't only be defined by what we don't do. What do we do for the LORD?
"For our offenses are many in your sight, and our sins testify against us. Our offenses are ever with us, and we acknowledge our iniquities:13 rebellion and treachery against the Lord, turning our backs on our God, inciting revolt and oppression, uttering lies our hearts have conceived" (Isa 59:12-13).