Psalm 51:19
1. Create in me a clean heart. Our old heart is evil from our youth (Genesis 8:21) and is deceitful above all things and desperately wicked (Jeremiah 17:5-10), and must be purged of the sin that indwells our affections and passions. For this to happen, our heart, which is the seat of the affections and passions of a human, must be created as clean. Create is defined as, "to form or make by investing with a new character." Our heart, filled with evil, was opened by the Lord. He took hyssop and dipped it in his blood, and then not just washed, but purged our heart. That was when we were saved. But as new Christians we still have much to learn, and at times we stumble, and we sin. So we come to God with a contrite heart and ask for forgiveness (Psalm 51:17), and He takes his hyssop and washes and purges our heart once more. After it has been purged again, He is willing to create a clean heart by filling it with a new character, so that the wicked heart that was once filled with evil is replaced with a clean heart that is filled with righteousness. Not our righteousness, but God's righteousness. How is that done? by searching His Word and meditating on it. By filling our heart with His Word so that, when temptation does arrive, it is His Word that is our thought and not our own fleshly desire (Psalm 119:9-16). I'm afraid that too many times Christians seek the Lord to purge them with hyssop and make them white as snow but then don't ask for Him to create a clean heart and so the evil that was once in this white heart soon returns. Ask the Lord to not only take the hate and bitterness but to also fill you with love. To take the deceit and fill you with truth. To take the selfishness and fill you with compassion. To take the fret and fill you with peace. Ask Him to create in you a clean heart.

2. Renew a right spirit within me. This is a result of you clean heart, because your spirit is your temper and disposition of mind, whether habitual or temporary. Don't be fooled into thinking that this will be an easy task, because it is a right spirit that will help you not yield to temptation. It is one thing to think instantly of Scripture when you are tempted, but thinking on Scripture is not doing what the Scripture says. It is your right spirit that will keep your heart clean. Your disposition is what you make it and unless you make it a right spirit, you can think about all the Scripture you want to but that isn't going to keep you from yielding to the temptation. Your heart will decide how you feel but your spirit will determine how you react. It will also determine how other people look at you. A right spirit is one that is "fit, suitable, proper, becoming, or straight." How properly do we portray Christ? How straight is our life? Romans 12:11 tells us that we are to be fervent in spirit serving the Lord, and Proverbs 29:23 tells us that we are to have a humble spirit. How is your spirit? Is it haughty? The Bible says that he that hath no rule over his spirit is like a city broken down and without wall. Let the Lord renew a right spirit within you so that you can keep that clean heart you asked Him to create.