אִֽישׁ־בַּ֭עַר לֹ֣א יֵדָ֑ע וּ֝כְסִ֗יל לֹא־יָבִ֥ין אֶת־זֹֽאת׃
דער בהֵמישער מענטש װײס ניט, און דער נאַר פֿאַרשטײט דאָס ניט.
Kli Yakar
The enemy said, “I will pursue, etc.” Pharaoh intended to do to Israel in the manner described in He makes nations great, and destroys them (Job 12:23), and as it says A brutish man does not know, and a fool does not understand this: when the wicked spring up like grass, and all the workers of iniquity flourish, it is so they may be destroyed forever (Psalms 92:7). For it is common practice in the world that one who wants to cast his fellow down to the ground, the higher he elevates him, the greater will be his fall, as one who falls from a high place cannot be compared to one who falls from a low place. As it says He has cast down from heaven to earth the glory of Israel (Lamentations 2:1). From a high roof to a deep pit. This is like the parable of a king against whom a poor and despised villager rebelled. What did the king do? He enriched and elevated him until he became very great, which astonished his servants. After he had remained in his elevated position for several years, the king took revenge on him, killing him and all his household, and took all that he had, leaving him no survivor or remnant. For then the revenge was more evident and publicized than if he had killed him while he was still lowly and unknown.
Rabbeinu Bahya
Onkelos believes that our verse speaks of G’d repaying the sinner generously for his relatively insignificant good deeds so that He will not have to use unrewarded good deeds as ameliorating the eventual punishment of such people in the hereafter. G’d chooses the inferior world to be the arena in which such sinners receive their rewards, a world which is brief and transient. By doing so, He is free to deny such people any share in the world to come, a world which is unending. It follows that what the onlooker perceives a the “good fortune” of the sinner in this life is actually part of his ill fortune, seeing it is the cause he will not enjoy life in the hereafter.
This is what David alluded to in Psalms 92,7: “a foolish man cannot know, a fool cannot understand זאת, this.” Such people as the ones David refers to do not understand the workings of the attribute זאת, the way the attribute of Justice works. This is also what is meant when the psalmist describes in the following verse: בפרוח רשעים כמו עשב ויציצו כל פועלי און—להשמדם עדי עד, “when the wicked sprout like grass and the evildoers blossom; it is only in order to destroy them forever.” G’d often treats the righteous in the opposite way by punishing him for his relatively few sins through inflicting pain and discomfort on him in this life so as to preserve his life in the hereafter fully intact.
This is what David alluded to in Psalms 92,7: “a foolish man cannot know, a fool cannot understand זאת, this.” Such people as the ones David refers to do not understand the workings of the attribute זאת, the way the attribute of Justice works. This is also what is meant when the psalmist describes in the following verse: בפרוח רשעים כמו עשב ויציצו כל פועלי און—להשמדם עדי עד, “when the wicked sprout like grass and the evildoers blossom; it is only in order to destroy them forever.” G’d often treats the righteous in the opposite way by punishing him for his relatively few sins through inflicting pain and discomfort on him in this life so as to preserve his life in the hereafter fully intact.
Rashi
brutish Heb. נבער. Comp. (Psalms 92:7) “a brutish (בער) man”; also here (infra 10:21), “the shepherds have become brutish (נבערו).”