What we do matters. Why we do what we do matters more.
"But the LORD said unto Samuel, Look not on his countenance, or on the height of his stature; because I have refused him: for the LORD seeth not as man seeth; for man looketh on the outward appearance, but the LORD looketh on the heart" (I Samuel 16:7).
"The word of God is quick, and powerful, and sharper than any twoedged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and is a discerner of the thoughts and intents of the heart" (Hebrews 4:12).
Apparently godly acts and behaviors are not necessarily authentic acts and behaviors of godliness. While it it is true that "ye shall know them by their fruits," it is also true that our capacity to evaluate the quality of produce is far from perfect (Matthew 7:16). There may well be a worm in the shiniest apple, and the seemingly righteous actions of ourselves or others may one day be revealed as having come forth from motivations other than those wrought in our redeemed spirits by the Holy Spirit. Again, our "What?," or that of others, may seem genuine. But our "Why?" may be faulty.
"Who can understand his errors? Cleanse thou me from secret faults" (Psalm 19:12).
There are few Biblical truths that more reveal our complete dependence on our Lord. We cannot understand our errors, that is, we cannot look into our own hearts, or the hearts of others. Thus, we cannot by ourselves know why we do that which we do. We require the penetrating gaze of the One whose eyes are "as a flame of fire," and unto whom "all things are naked and opened" (Psalm 19:12; Hebrews 4:13). We must approach our Heavenly Father often for His searching and cleansing of thoughts and intents, and the purification of our motives. He alone can accomplish the task, because He alone can perfectly see the "errors" and "secret faults" that compromise our relationship with Him and others.
While challenging, this truth is also greatly liberating. We trust the Lord to do His searching work, and we leave the matter with Him rather than attempting to see that which we cannot see. We have a role, of course, and the Holy Spirit will lead us to His Word and to fellowship with likehearted believers as we seek to walk with the Lord Jesus in purity of heart and motive. However, we do not exercise the excessive introspection that is paralyzing to authentic godliness, and devastating to our experience of the peace and joy of Christ. We rather "examine yourselves" from the same basis whereby all things are fulfilled in our lives (II Corinthians 13:5). We trust and submit ourselves to God, rest in His faithfulness, and then actively respond to His illumination and moving within our hearts and minds by the enabling He provides.
"Why?" Only God can reveal the answer. And only God can ensure the proper answer. We do well to approach Him often with request for the searching of our thoughts and intents, as David so perfectly and beautifully asked in as he acknowledged our Lord's gaze upon the heart...
"Search me, O God, and know my heart: try me, and know my thoughts: and see if there be any wicked way in me, and lead me in the way everlasting: (Psalm 139:23-24)