Who can have compassion on the ignorant, and on them that are out of the way… – Hebrews 5:2

What do we know of sin? The larger proportion of our sins are probably unknown to us. We do them, and scarcely observe that we have committed them. And who knows the evil that lies in any one sin? Who is he that can weigh his iniquities in scales, or his errors in balances? Upon that one dread subject of sin, we are all life babes; we have not begun to learn more than the alphabet of that awful knowledge. Sinful we are, but it is part of the effect of sin that we do not know the extent of our sinfulness, and we should not know it at all, if it were not for the teachings of the Holy Spirit.

Again, what do we know of ourselves? Does any man truly know himself? “The proper study of mankind is man,” says Pope. I am not sure of that; but I am certain that the proper study of mankind is Christ; for in Him we not only can learn about man, but much more besides. But how little we know of ourselves, of our natural weakness, of our evil tendencies, of our proneness in this direction, or in that! “Who can understand his errors? Cleanse Thou me from secret faults.”

What do we know of God the unsearchable? Is He past finding out? Who can sufficiently tell of His nature, or of His wondrous attributes? Who can speak adequately of His greatness, or of His glory? Who can number up His years, or declare the whole of His lovingkindness? “O the depth of the riches both of the wisdom and knowledge of God! How unsearchable are His judgments, and His ways past finding out!” As compared with the light of God, we are in the dim twilight. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/2251.cfm