God is so much concern about the state of our heart than anything else, because God does not see the way we see He always look into our heart before we can be acceptable in His sight.
1 Samuel 16:7 says ….. For the LORD seeth not as man seeth; for man looketh on the outward appearance, but the LORD looketh on the heart. God describe the heart of man in Jeremiah 17:9-10.
The heart is deceitful above all things and desperately wicked who can know it? I the LORD search the heart, I try the reins, even to give every man according to his ways, and according to the fruit of his doings.
Before any man can be acceptable and approved of God, his heart must be pure.
Many people are seeking God but they could not find Him why?
The answer is simply because their heart is not pure.
The only sets of people that have the access of seeing God are the pure in heart.
Matthew 5: 8 – Blessed are the pure in heart:  for they shall see God.
Whenever you want to seek the face of the Lord you must ensure your heart is pure, the psalmist said in chapter 66:18. If I regard iniquity in my heart, the Lord will not hear me. For anyone to receive the blessings of the Lord, or to ascend to the hill of the Lord and to stand in stand in His holy place he must have a clean hand and a pure heart Psalm 24:3-5
How will a man make his heart pure? The Bible says, Blessed are the undefiled in the way, who walk in the law of the LORD. Blessed are they that keep his testimonies and that seek him with the whole heart. They also do no iniquity they walk in his ways. Psalm 119:1-3.
The Psalmist went on and in verse 9 Wherewithal shall a young man cleanse his way?  By taking heed thereto according to thy word.
The Word of God is all we need to make our heart pure.
The Psalmist also said in 119:11 Thy word have I hid in mine heart, that I might not sin against thee. This means if we allow the Word of God in our heart it shall become pure because the Word of God is truth. Jesus prayed in John 17:17. Sanctify them through thy truth: thy word is truth.
The Word of God is the water that we can use to wash our heart to make it pure day by day Ephesians 5:26.
David was preferred and chosen among his brethren to be the king of Israel because God found him to be a man after His own heart, but when David committed sin by killing Uriah the Hittite with sword, and taken his wife God was angry with him and God sent Nathan the prophet to him, he acknowledge his sin before the Lord then he prayed for forgiveness of sin and ask God to create in him a clean heart.
Psalm 51:10 Create in me a clean heart, O God; and renew a right spirit within me. David is a very good example for us Christians that we need a clean heart to be acceptable before God. May the LORD give us a pure heart as we pray and receive His Word into our heart in Jesus mighty name.