Albert Barnes Commentary Isaiah 5:20

"Woe unto them that call evil good, and good evil; that put darkness for light, and light for darkness; that put bitter for sweet, and sweet for bitter!" — Isaiah 5:20 (ASV)

Wo unto them that call evil good ... - This is the fourth class of sins denounced. The sin which is condemned here is that of “perverting and confounding” things, especially the distinctions of morality and religion. They prefer erroneous and false doctrines to the true; they prefer an evil to an upright course of conduct. The Chaldee renders this, ‘Wo to those who say to the impious, who are prospered in this age, You are good; and who say to the meek, You are impious.’ Jarchi thinks that the prophet here refers to those who worship idols, but he evidently has a more general reference to those who confound all the distinctions of right and wrong, and who prefer the wrong.

That put darkness for light - “Darkness,” in the Scriptures, is the emblem of ignorance, error, false doctrine, crime. Light denotes truth, knowledge, piety. This clause, therefore, expresses in a figurative but more emphatic manner what was said in the previous part of the verse.

That put bitter - “Bitter and bitterness” are often used to denote “sin;” see the note at Acts 8:23; also Romans 3:14; Ephesians 4:31; Hebrews 12:15; Jeremiah 2:19; Jeremiah 4:18. The meaning here does not differ from that expressed in the other parts of the verse, except that there is implied the additional idea that sin is bitter, and that virtue, or holiness, is sweet: that is, that the one is accompanied by painful consequences, and the other with pleasure.