There shall no evil—mischief—happen to the just. The mischief (aven) intended is not misfortune, calamity, but the evil consequences that follow on ill-doing (Proverbs 22:8); from these the righteous are saved.
Our Lord goes further, and says (Matthew 6:33), "Seek ye first the kingdom of God, and his righteousness; and all these (temporal) things shall be added unto you." Vulgate, "Nothing that happens can make a just man sorrowful;" for he knows it is all for the best, and he looks toward another life, where all seeming anomalies will be cleared up.
Septuagint, "The just man takes pleasure in naught that is unjust." The wicked shall be filled with mischief; rather, with evil, moral and physical (Psalms 32:10). The Old Testament takes a general view of God's moral government without regarding special anomalies.