Psalm 14 (excerpted)
The God who sits enthroned on high
The foolish in their heart deny;
Not one does good; corrupt in thought,
Unrighteous works their hands have wrought.
“What things they do understand by instinct, like unreasoning animals— these are the very things that destroy them.” What is Jude trying to say? He means that persons without spiritual discernment are abysmally ignorant of reality and depend on instinct. That is, they have lowered themselves to the level of animals and in their sexual pursuits (see v. 8) are guided by instinct. Yet, unlike the animals which abide by the laws of nature, these godless men are destroyed by the very things they fail to understand. When men live by instinct, they abandon even natural law and consequently perish. They place themselves on a par with the animals, but because of their refusal to obey even the laws God has placed in nature, they are destroyed (compare Rom. 1:24).