You keep yourself pure because you appreciate purity or because you hate to be dirty. Keeping your heart pure is not possible with your own strength neither with human cleaners.
Dirty or pure?
When do you consider yourself dirty? Everybody has his own standards on dirtiness and purity. This is true concerning the dirtiness of clothes and human body and much more with the dirtiness of heart.
The things that make your heart dirty come from both outside and inside you. What you hear, see or feel can make your heart dirty and also what you think, say or do. Because your bad thoughts have been food for your inner man, you have become a sinner. You are what you have thought.
Did the ears of your spirit rejoice at a dirty thought and did the mouth of your spirit eat fruit of pride? Did the eyes of your spirit admire a filthy sight and did the eyes of your soul fasten on greediness? Did the members of your spirit feast on an unclean feeling and did the hands of your spirit reach for dissolute selfishness?
Your bad thoughts are the dirt which tempts you to do evil things that are condemned by your conscience. The being produced by your bad thoughts is the sin that lies in ambush at the door of your heart. Its desire is for you, and you cannot rule over it, if your spirit is deadened by your guilt. When you open your heart for bad thoughts sin occupies you so that you cannot make a difference between it and your ego.
Although sin has killed you, clean thoughts can make your spirit alive again. If you have not awoken to desire clean thoughts, you cannot get a clear conscience. If you don't want to face the judgments of your conscience, you don't allow clean thoughts to settle down in you either.
Of what kind of dirt you, in your opinion, should be cleansed? In this matter we usually follow the public standard. If you face someone who is more pure than you, you realize yourself to be unclean. Jesus, the Son of God is pure! Compare yourself to Him. He who loves God, adopts the opinion of Jesus about what is dirty and what is pure.
God's words can wash you pure. Let the ears of your spirit rejoice at His pure thoughts and let the mouth of your spirit eat fruit of the humbleness of Jesus. Let the eyes of your spirit admire the revelation of God's love on Golgotha and let your soul fasten on the sacrifice of God. Long for the presence of Jesus and enjoy peace given by His grace and reach the hands of your spirit for His deeds.
When Jesus purifies you with His words, your conscience will wake up from its dormancy. Then you will feel guilty and you begin to thirst after God's grace. If you confess your sins to Jesus, His atoning blood will touch your spirit and purify your conscience. Then He also separates your spirit from the ego of your bad thoughts with the sword of His word and you become a new creation, if you let Him do this circumcision of your heart! Starting from this moment your spirit has power to resist the thoughts of your old ego.
Do you appreciate the purity of God? Maybe you are satisfied if you are pure in the eyes of men, although you are unclean in the eyes of God. If you are going to get to Him, you have to be purified.
Pure heart and clear conscience
If you feel that your conscience doesn't accuse you, it doesn't mean that your heart would be pure. If the thoughts and attitudes of your heart are after God's heart then your heart is pure. If you are satisfied with getting forgiveness of your sins and having a good conscience, you are in danger of falling again.
Don't only reach for a good conscience and a salvation from the judgment of God, but ask for a change of your mind and for purging of your thoughts. The water of God's word changes your thoughts and attitudes. This means that you ask for yourself light of God's word that rebukes you.
If we live according to the thoughts of God then we live in light. If we live according to our dirty thoughts we live in darkness. The blood of Jesus cannot cleanse our conscience in the darkness of our unclean thoughts.
"But if we walk in the light as He is in the light, we have fellowship with one another, and the blood of Jesus Christ His Son cleanses us from all sin." 1Jo.1:7
If you don't watch over your thoughts, you will fall into the power of darkness. Let the stream of your consciousness follow Jesus. If the Holy Spirit lives in you, you are able to watch yourself just by His influence. When you notice that a dark thought tries to come into your consciousness, immediately pray to Jesus to help you to reject it.
If you didn't watch, you fell into darkness and sinned. If the Holy Spirit lives in you, He will grieve in you and wait for you to come soon away from the darkness to the light of God so that He could give you forgiveness. However if you love to be in the darkness, you will finally claim that you have done nothing wrong. "If we say that we have no sin, we deceive ourselves, and the truth is not in us." 1Jo.1:8
Power of the blood of Jesus
God has created for us a conscience that demands punishment for evil deeds. Therefore the sacrifice of Jesus is needed so that we could be set free from our guilt. Either you yourself suffer or the Lamb of God suffers your punishment. The conscience of many people doesn't accept a vicarious sacrifice and therefore they don't believe in Bible's Jesus. This results from some religious ceremony that has given their conscience a false peace.
Those religious acts are dead works. You can be released from their hold only after you have experienced the power of the blood of Jesus. "How much more shall the blood of Christ, who through the eternal Spirit offered Himself without spot to God, cleanse your conscience from dead works to serve the living God!" Heb.9:14
You cannot serve the living God, if your conscience has gained peace by trusting on any other thing than the sacrifice of Jesus and on the power of His blood.
How can the power of the blood of Jesus affect in your heart? Firstly you must be in the faith of Jesus. To be able to experience the power of the blood of Jesus He must live in your heart by faith. If He is outside He cannot wash from the inside.
Secondly you must confess your sin just as the truth is. "If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness." 1Jo.1:9
You must confess your sin to God with all your heart, in thoughts, in words and in deeds. Think about your deed deep in your heart, confessing your evilness that gave birth to your bad deed. Don't speak to God only about your bad deeds, but abhor your bad thoughts and attitudes that have caused your deeds. Repent your thoughts and accept your responsibility for your bad deeds. Prove by thinking and saying right that you want to change.
Many ask forgiveness for their bad deeds only because they are afraid of the punishment but they don't want to change their thoughts. God doesn't forgive you only because you asked. He forgives you because you repent your evilness and you confess your sins.
By confessing your sins you ask for forgiveness. By defending your sins you ask for judgment. What you confess in the light of God's words that is washed away by the blood of Jesus.
"Therefore, brethren, having boldness to enter the Holiest by the blood of Jesus ... let us draw near with a true heart in full assurance of faith, having our hearts sprinkled from an evil conscience and our bodies washed with pure water." Heb.10:19-22
If the body of our thoughts has been cleansed by the water of God's word and our conscience has received the atonement with the blood of Jesus, we are able to enter the dazzling brightness of the face of God.