God makes it clear why we sin - it's a matter of the heart. Our hearts have been inclined toward sin from the time we were born. It is easy to fall into the routine of forgetting and forsaking God. But we can still choose whether or not to continue in sin. We can yield to a specific temptation, or we can ask God to help us resist temptation when it comes. A great verse goes with that. Jeremiah 17:9-10 says, "The heart is deceitful above all things and beyond cure. Who can understand it? 'I the Lord search the heart and examine the mind, to reward a man according to his conduct, according to what his deeds deserve.'"
God wants a broken spirit and a broken and contrite heart. You can never please God by outward actions - no matter how good - if your inward heart attitude is not right. Are you sorry for your sin? Do you genuinely intend to stop? God is pleased by this kind of humility. Are you seperated from God by sin? No matter how far you have wandered, God promises a fresh new beginning if only you will turn to him.
Matthew 12:34 ends by saying, "For the mouth speaks out of that which fills the heart." What is coming out of your heart? What we say receals ehat is in our hearts. You can't solve your heart problem, however, just by cleaning up your speech. You must allow the Holy Spirit to fill you with new attitudes and motives; then your speech will be cleansed at it's source.
Keep listening to God. Your heart will keep changing. Don't let what's in your heart hold you captive. Our old way of life before believing in Christ is completely in the past. We should put it behind us and never look back. We are not to be driven by desire and impulse. We must put on the new role, head in the new direction, and have the new way of thinking that the Holy Spirit gives us.
Dear God, I just pray that you would take my heart and make it yours. Transform it. Clean the sin and captivity that's inside of it. Please just break my heart only so that you can make it whole again.