John Gills Exposition of the Bible Commentary - Proverbs 24:9
The thoughts of foolishness is sin ,.... The thought of sin is sin F5 "Nam scelus intra se tacitum qui cogitat ullum, facti crimen habet", Juvenal. Satyr. 13. v. 209, 210. , before it comes into action; the motions of sin in the mind, the workings of corrupt nature in the heart, the sinful desires of the flesh and of the mind: these are forbidden and condemned by the law of God as sin, which says, "Thou shall not covet", Exodus 20:17 , and stand in need of pardoning grace and... read more
Matthew Henry's Complete Commentary - Proverbs 24:7-9
Here is the description, 1. Of a weak man: Wisdom is too high for him; he thinks it so, and therefore, despairing to attain it, he will take no pains in the pursuit of it, but sit down content without it. And really it is so; he has not capacity for it, and therefore the advantages he has for getting it are all in vain to him. It is no easy thing to get wisdom; those that have natural parts good enough, yet if they be foolish, that is, if they be slothful and will not take pains, if they be... read more