Psalms 73:12

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 embarrassed by the fact that the wicked are prosperous and happy. The meaning is, “Lo, these are wicked people - people of undoubted depravity; they are people who live regardless of God; and yet they are peaceful, tranquil, happy, prospered.” This was one of the facts which so much embarrassed 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 rendered “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.