Today we see the second effect of the changed life of the believer. Jesus says that the pure in heart will be happy. But one may ask “how does one attain a pure heart?” Only Jesus can give a pure heart and we see how it is attained by looking at the second beatitude (those who mourn). The fifth beatitude(the pure in heart) is the reaction of one who has experienced the second one. Those who mourn over their sin can attain a pure heart.
The pure heart is given by God for those who have repented of their sin. It is impossible to repent over something that we do not realize, or are not truly sorry for. Those who have mourned over their sin have only done so in the light of the perfection of Jesus Christ and His Word. When we come into His presence, realize our sin and become sorrowful for it, we repent of it. Repentance is the key to purity. We cannot cleanse ourselves from our own sin, it has to be done by Jesus the perfect sacrifice. When He forgives us, our sin is not covered, it is instead removed. We see in Hebrews chapter 10 that the blood of bulls and goats could never take away sin. It was reminder each year as they were offered. It states that if those things could have removed sin they would not have stopped being offered. But they were only a shadow of the good things to come in Christ Jesus who removes our sin once and for all. There was no happiness in the law and in sacrifices because all they did was remind mankind that we had fallen short of God’s righteousness. Now in Christ we have put on His righteousness (Ephesians 4:24).
Our happiness comes by the knowledge that He has removed our sin and that we can be secure in His righteousness not our own. I John 5:13 states “I write these things to you who believe in the name of the Son of God so that you may know that you have eternal life.” We will stand pure before Him! And when we do sin after repentance, is says in I John 1:9 that “if we confess our sin God is faithful and just to forgive us of our sins and cleanse us from all unrighteousness.” The joy of a pure heart comes by the atoning blood of Jesus Christ who has forgiven us and has chosen to do so before the foundation of the world.