How often have you responded, “I don’t know,” when asked, “Why did you do that?” Even when we try to discern our motives, it’s hard to see the “sin behind the sin” because we’re not impartial examiners. Out of a deep desire to feel good about ourselves, we don’t want to look too closely at the motives that drive our behavior.
Ultimately, the only One who knows us completely is God. The psalmist writes:
O LORD, you have searched me and known me! You know when I sit down and when I rise up; you discern my thoughts from afar. You search out my path and my lying down and are acquainted with all my ways. Even before a word is on my tongue, behold, O LORD, you know it altogether. (Ps. 139:1–4)
In one sense, this psalm is tremendously comforting: Before I was born, God knew me. He knit me together in my mother’s womb. He determined the number of my days. God knows me completely. Nothing in my life is hidden from God. He knows the good, the bad, and the ugly about me, and He still loves me.
In another sense, Psalm 139 is terrifying. There are thoughts, attitudes, and desires I’m aware of in myself that I would be ashamed to have other people know. People can see what I do and hear what I say, but they don’t know what is driving my heart. For that matter, I can’t always figure out what’s driving my heart. I can hide the sin inside from other people and even from myself, but not from God. He knows me completely. There is nowhere in the universe where I can hide from Him.
Yet, with amazing vulnerability, the psalmist invites a thorough examination of his heart: “Search me, O God, and know my heart! Try me and know my thoughts! And see if there be any grievous way in me, and lead me in the way everlasting!” (vv. 23–24).
Our ability to willingly and honestly face the truth about our motives depends on what we really believe about the gospel. We sing: “Let not conscience make you linger, nor of fitness fondly dream. All the fitness He requires is to feel your need of Him.”
If your conscience is weakened by a longing for “fitness”—that God’s approval of you depends on what you do to make yourself acceptable—then honesty about your heart’s motives will be too threatening. Boldness to face the truth about your heart grows out of confidence in the justifying grace of God in Jesus Christ. If God is for you, who can stand against you (Rom. 8:31)? If nothing in all creation can separate you from the love of God in Christ Jesus, that includes your sin.
The invitation to be known completely stems from confidence in the character of God. He is merciful and gracious, slow to anger and abounding in steadfast love (Ps. 103:8). “If God is for us,” we don’t have to be afraid of what God will find in our hearts. The search is not for His benefit but for ours. God already knows the motives and misplaced desires behind our outward sin. For God to show us what’s driving our hearts and to lead us toward repentance is for our good, that we might be set free from the controlling power of remaining sin.