Albert Barnes Commentary Psalms 73:12

"Behold, these are the wicked; And, being alway at ease, they increase in riches." — Psalms 73:12 (ASV)

Behold, these are the ungodly, who prosper in the world - This is also to be understood as the language of the good man, perplexed and troubled by the fact that the wicked are prosperous and happy. The meaning is, “Look, these are wicked people—people of undoubted depravity. They are people who live without regard for God, and yet they are peaceful, tranquil, happy, and prosperous.” This was one of the facts that so greatly troubled the psalmist. If there had been any doubt about the character of those people, the case would have been different. But there was none. They were people whose character for wickedness was well known, and yet they were permitted to live in peace and prosperity, as if they were the favorites of heaven.

The literal meaning of the words translated as who prosper in the world is, “tranquil (or secure) for the age;” that is, forever, or constantly. They know no changes; they see no reverses; they are the same through life.

They are always tranquil, calm, happy, successful.

They increase in riches - Literally, “They become great in substance.” They make constant accumulations in wealth, until they become great.