A clean heart
The word for pure here Katharos (kahthar-Ros) means clean, clear pure. And it was a word that the Jewish people of the first century were used to hearing, especially from the Pharisees, who emphasized ceremonial cleanness.
Focusing on their manmade rules had caused them to live their lives working against God, keeping people out of heaven who knew that they couldn’t follow all of the Pharisees rules and requirements, and so assumed that this meant that God just didn’t want them either. The Pharisees liked it this way, because it left them with all of the power to control people’s lives, and all of the prestige and honor of being looked up to as a Rabbi. Jesus condemns them repeatedly, and especially in Mathew chapter 23. In 23:25-26 Jesus says 25 “Woe to you, scribes and Pharisees, hypocrites! For you clean the outside of the cup and of the dish, but inside they are full of robbery and self-indulgence. 26 You blind Pharisee, first clean the inside of the cup and of the dish, so that the outside of it may also become clean. It gives us big clues as to what Jesus means when He talks about having a clean heart. And Jesus’ words emphasize that God is not interested in outward appearances.
A pure/whole heart
This word katharos (kahthar-Ros) can also be thought of as those who are pure in heart. Un-adulturated—whole-hearted in purpose and motive.
And this means being sincere. We often think of the word sincere as being truthful, but in the New Testament it carries the connotation of being Genuine. The real thing. This word refers to something completely clear, free from hypocrisy (deceit, wickedness) which stands in the full light of God’s approval. A life truly transparent before God and men, without any deviousness, ulterior motives, or impure motivation. Without wearing a mask, without playing a role, and without guile. A person who has a pure heart is one who is single-hearted, not divided in heart. Serving God faithfully, not serving God and something else alongside God.
We can’t purify our own heart
Well, Jesus demonstrated that the Pharisees hadn’t been able to purify their own heart, despite working tirelessly at following man-made rules based on God’s law given to Moses. God put our conscience inside us to guide us: Proverbs 20:27 says, “The spirit of a man is the lamp of the Lord, searching all the inner depths of his heart.” Our conscience is like a warning light on the dash of our car, but unfortunately, like the “low oil” light on some cars, once the light comes on, there is probably already damage being done. As we give in to our sinful nature, it warps our conscience more and more. Sin distorts the conscience, blurs the line between right and wrong, and blinds us to the truth. A guilty conscience not only affects how we view ourselves, and what we’ll tolerate in our own behavior, it also affects the way we look at others. For example Mathew 7:3-5.
God does the cleaning and the purifying
God has already done what is necessary. He sent Jesus to die on the cross not only so that our sins could be paid for, but so that our conscience can be cleansed by His blood. The only detergent that is effective in cleaning a guilty conscience is the blood of Jesus. The Bible says, in Hebrews 9:14 “How much more, then, will the blood of Christ, who through the eternal Spirit offered himself unblemished to God, cleanse our consciences from acts that lead to death, so that we may serve the living God.
We believers also know that we still mess up from time to time, which of course messes with our conscience. Well, our loving God has thought of this as well, and has provided for us.
Ephesians 5 v.26-27 says that He saved us the church 26 so that He might sanctify her, having cleansed her by the washing of water with the word, 27 that He might present to Himself the church in all her glory, having no spot or wrinkle or any such thing; but that she would be holy and blameless. It’s the reading of the Word of God and applying it to our lives that God uses in this process of sanctification. As Jesus prayed for the church in John 17:17 “Sanctify them in the truth; Your word is truth.”
So, God’s word will correct us, realign us to God’s standard, if we will conform ourselves to it, and allow God to transform us into the image of Jesus
We must be careful to let the Holy Spirit use the Word of God to re-calibrate our thoughts, our ideas, the way that we think things should be so that we will be in line with what the Lord wants us to do, and with what the God thinks is right and wrong. We can have all sorts of ideas, but we must always make sure that they line up with the Bible. We read in II Timothy 3:16-17: “All scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness, so that the man of God may be thoroughly equipped for every good work.” God’s Word always points you to Jesus and He becomes your standard for right and wrong, and for how to live as a Citizen of the Kingdom.
For they will see God
Our applying the Word of God to our lives gets us ready to see the Word in person, Jesus. This process of sanctification that happens in the Christian life is getting us ready to meet Jesus. And it is important that we are ready to see Him, and have a presentable heart when we do. David emphasizes that it is the purity of our heart that matters when we approach God, saying in Psalm 24 3-4 Who may ascend onto the hill of the Lord? And who may stand in His holy place? 4 One who has clean hands and a pure heart, Who has not lifted up his soul to deceit And has not sworn deceitfully.
So, begin a relationship with Jesus, let Him wash you in His heart, soul and conscious-cleansing blood. Allow Him to wash you with the water of the Word, as you apply it correctly to your life, and cooperate with His plan for your sanctification, doing His work in sincere love for Him and for one another in preparation for meeting Him someday and hearing the words “well done good and faithful servant”