2 My feet had almost stumbled, my steps had nearly slipped.
3 For I was envious of the arrogant when I saw the prosperity of the wicked.
4 For they have no pangs until death; their bodies are fat and sleek.
5 They are not in trouble as others are; they are not stricken like the rest of mankind.
6 Therefore pride is their necklace...
12 Behold, these are the wicked; always at ease, they increase in riches.
13 All in vain have I kept my heart clean and washed my hands in innocence.
14 For all the day long I have been stricken and rebuked every morning.
So the man or woman who believes cries out, "WHY?" in the face of such injustice, because it is so unfair, and then thinks of God as approving what these evil men and women do because He is silent.
However, that's not the end of the story. Nobody really gains a thing from rejecting God, and living as if this life alone is "all there is;" nobody gains a thing from arrogance, and violence, and covetousness that destroy other people, because:
17 ...I went into the sanctuary of God; then I discerned their end.
18 Truly you set them in slippery places; you make them fall to ruin.
19 How they are destroyed in a moment, swept away utterly by terrors!
So the actual question these folk should ask is, "what happens at the end?" How will God see me? This is a continuous theme in the Scriptures--a man who rejects God does so without considering that his life here will end, and what does he have then?
If you believe, on the other hand, you inherit the testimony of the writer of this Psalm, thus:
23 ...I am continually with you; you hold my right hand.
24 You guide me with your counsel, and afterward you will receive me to glory.
25 Whom have I in heaven but you? And there is nothing on earth that I desire besides you.
26 My flesh and my heart may fail, but God is the strength of my heart and my portion forever.
If you have Him, you have everything, and you have it forever. If you don't have Him, even what you seem to have will be taken from you, and you will face eternity naked and empty-handed.