9The thought of foolishness is sin: and the scorner is an abomination to men.
1 Corinthians 1:18
18For the preaching of the cross is to them that perish foolishness; but unto us which are saved it is the power of God.
1 Corinthians 3:19
19For the wisdom of this world is foolishness with God. For it is written, He taketh the wise in their own craftiness.
14Wise men lay up knowledge: but the mouth of the foolish is near destruction.
5O God, thou knowest my foolishness; and my sins are not hid from thee.
23A prudent man concealeth knowledge: but the heart of fools proclaimeth foolishness.
24The crown of the wise is their riches: but the foolishness of fools is folly.
2The tongue of the wise useth knowledge aright: but the mouth of fools poureth out foolishness.
14The heart of him that hath understanding seeketh knowledge: but the mouth of fools feedeth on foolishness.
3The foolishness of man perverteth his way: and his heart fretteth against the LORD.
(Special thanks to Doctrine Matters Bible Topic Guidebook by Missionary spencer smith.)