“Let not sin therefore reign in your mortal body, that ye should obey it in the lusts thereof.” Romans 6:12
When God commands us to do something, He also gives us the power to do it. If we answer His command with “I can’t,” we are lying. The honest answer is “I won’t,” because with God we can do anything.
God tells us not to sin because sin mars our fellowship with Him; it erects a wall. Sin causes us to walk in darkness, blinding our eyes to the path. God hides His face from us, the Holy Spirit is grieved, and we lose His power. We lose peace and we become servants to the ruthless taskmaster Satan. Sin brings unwanted consequences, ending in death.
If our sin is unforgiveness, God gives us over to the tormentors. If our sin is dabbling in the occult, we will be depressed, oppressed, or possessed by demons. If pride, we will fall. If immorality, our souls will be destroyed. If anger, our relationships will be ruined. If worry, we will lose our peace. If bitterness, all will be troubled and many defiled.
“Likewise reckon ye also yourselves to be dead indeed unto sin, but alive unto God through Jesus Christ our Lord.” Romans 6:11