A man is seeking worship of God in the Holy Presence of the Lord. He knows he must qualify for entrance into a sweet fellowship with his Lord. He asks God to examine his outer behavior (walk) and inner thoughts (reins and heart).
Although he claims integrity and faithfulness and innocence, he finally realizes he needs redemption and grace and so he asks for mercy and lovingkindness. The fundamental and final qualification for admission into His Presence is God’s mercy. Access to God is not earned nor given as a right. It is freely granted for Jesus’ sake.
The believer loves the habitation of God’s house; he seeks fellowship with Him constantly. Friendship with his loving Lord far surpasses association with vain persons, dissemblers, evildoers and sinners, with the world. The world is the place where our enemies lurk and prowl; it is used by Sin and Satan to bring us into misbelief and despair and other great shame and vice.
Daily repentance and faith in Christ ushers us from the defeated kingdom into the kingdom of the Overcomer where our Friend is waiting with open arms.