David W. Henderson says, "Pride is amnesia of the soul. It is forgetting God."
Unbelievers forget God by refusing to seek Him; "The wicked are too proud to seek God. They seem to think that God is dead" (Psalm 10:4).
But for believers, pride often manifests itself in living apart from God in foolish self-confidence. Pride makes monuments out of our deeds of self-reliance. Because the Lord allows us some room to live in independence from Him, we deceive ourselves into thinking that what we've done, or are doing, is a result of our wisdom, strength, talents, or abilities. The foolish unbeliever has said, "There is no God," but the foolish believer says, "There is no need of God in what I am aiming to do." This is the height of arrogance.
Personal success and prosperity seductively erode our memories of God's work on our behalf, and subtly we drift into the delusion of claiming what is God's as belonging to ourselves.
It moves us from a vertical relationship with God to a horizontal trust in ourselves.
"Trust in the Lord with all your heart; do not depend on your own understanding. Seek his will in all you do, and he will show you which path to take. Don't be impressed with your own wisdom. Instead, fear the Lord and turn away from evil" (Proverbs 3:5-7).
(Commentary Mark Martin)