The heart is deceitful above all things, and desperately wicked: who can know it? Jer. 17:9
"Thus saith the Lord; Cursed be the man that trusteth in man, and maketh flesh his arm, and whose heart departeth from the Lord. For he shall be like the heath in the desert, and shall not see when good cometh; but shall inhabit the parched places in the wilderness, in a salt land and not inhabited. Blessed is the man that trusteth in the Lord, and whose hope the Lord is. For he shall be as a tree planted by the waters, and that spreadeth out her roots by the river, and shall not see when heat cometh, but her leaf shall be green; and shall not be careful in the year of drought, neither shall cease from yielding fruit" (Jer. 17:5-8). Here is a contrast between the one who trusts in the Lord and the one who trusts in flesh, or himself. The book of Psalms says that he who trusts in his own heart is a fool.
Today's text says that the human heart is deceitful--even as to whether we are trusting in God or in ourselves. Have you ever thought you were trusting in God but discovered that you were trusting in yourself, and you didn't know it until you had a horrible fall, showing how deceitful your heart really was? God, in His kindness, has made provision to search our hearts and test our minds.
"God leads His people on, step by step. He brings them up to different points calculated to manifest what is in the heart. Some endure at one point, but fall off at the next. At every advanced point the heart is tested and tried a little closer....Here they have opportunity to see what is in their hearts that shuts out Jesus."--Testimonies, vol. 1, p. 187.
A person who is abiding in Christ's strength experiences the power of God so that sin has no dominion over him. "He [Christ] abides in your heart by faith. You are to maintain this connection with Christ by faith and the continual surrender of your will to Him; and so long as you do this, He will work in you to will and to do according to His good pleasure."--Steps to Christ, pp. 62, 63. (Italics supplied.) It is not our part to keep examining ourselves moment by moment to see whether we are abiding in His strength. We may not be able to judge correctly. Our part is to continue our relationship with Christ by faith, through daily communion with Him, and He will bring us the victory.