These two little verses from James give us a huge lesson:
Becoming close to God requires humility, and for us to resist the devil. This resistance agains the devil is equated with repentance from sin and rejection of worldliness. If we do this, then our heart is pure because our focus is on God and our desires are in line with His.
God called David a man after His own heart because he understood this. And, when he chose sin and the world, he recognized it was more than just sin, it was an impure heart. So in Psalm 51 he repented, asked the Lord for mercy and forgiveness and prayed, “Create in me a pure heart, O God, and renew a steadfast spirit within me.” Psalms 51:10
I pray that my heart would be pure and loyal to God too. “Blessed are the pure in heart for they shall see God.” (Matthew 5:8) I want to see Him!