Man's heart is the spiritual center of his being. Out of it come all the issues of his life from a spiritual point of view, even as out of his physical heart comes all the blood which every part of his body needs. In Psalm 139:23the psalmist presents this prayer, "Search me, O God, and know my heart; try me, and know my thoughts."
This is an awesome request. So often we like to have our hearts hidden from God's eyes. Adam and Eve, after they fell into sin, tried to hide away from God. Certainly the question is whether we want God to know what desires are in our hearts and minds. We do not want Him to know what we hate and what we love, for we know that He does not approve of what is in our souls as we are by nature.
The question certainly arises: How does the psalmist dare to pray to God this request that He search his heart? Is not our desire that He look away from our hearts rather than into them? Do we want Him to see the hatred we have for spiritual things? And do we not rather prefer that He look at only some of our outward activities?
The psalmist is not haughty and proud, boastful of how good he is. He is humble. He prays that God will deal with him as one in whom He has implanted love of God, and see him as a reborn child of God in whose heart He has implanted the new life of spiritual difference from that wherewith he was born. He wants God to see him as a child of God.
Let us bring to God this prayer. Let us pray that, because He began salvation in us, He will bless us further by causing us to walk even more often and fully in love to Him.
This is a humble prayer that God may deal with us as those whose sins He has blotted out by His Son, and as those in whom He has begun the work of salvation. It is a prayer to be dealt with as Christians, and as those whom Christ has already changed spiritually.
Read: Psalm 139 .
… In short, in order to walk uprightly, we must necessarily put away ‘respect of persons’, which obscures the light and perverts right judgment, as God frequently inculcates in the Law, (Deuteronomy 1:16;16:19,) and as experience also points out. - John Calvin