Gods justice seeming hidden in the short term but triumphing in the end. Goes into a lot of detail about how the ungodly are unfair and arrogant. This is cut from personal pain!
So what is the answer when life is unfair? The writer makes no bones about it challenging his faith. He accuses God of being distant and hiding: uncaring and cowardly. He doesn’t deny that ignoring God works: “his ways are always prosperous”. He emphasises the eternal nature of food and the psalm is a call on god to act, arise, remember the weak and godly and crush the exploiters.
It’s a bit unconvincing because it acknowledges that early justice is not always there, so it’s a poem of yearning.