Siman 596

(153.) He said [Psalms 92]: "A boor does not know, and a fool does not understand this" — they do not know and understand this matter, the fools and boors — "When the wicked flourish like grass and all evildoers blossom — it is to destroy them forever." Why should He let them flourish and then destroy them forever? ... But in truth "the ways of G-d are upright" — "and there is no injustice in Him" — only it is impossible to understand this with any human intellect.