Commentaire sur L’Ecclésiaste 7:16

Be not exceedingly righteous. Like Shaul, who tried to display his righteousness and [misdirected] his mercy on the wicked.

“Do not be overly righteous, and do not be exceedingly wise; why should you be be destroyed?” (Ecclesiastes 7:16)
“Do not be overly righteous, and do not be exceedingly wise.” “Do not be overly righteous” – more [righteous] than your Creator; this is a reference to Saul, as it is written: “Saul came to the city of Amalek [and lay in wait [vayarev] in the valley]” (I Samuel 15:5). Rabbi Huna and Rabbi Benaya say: He began deliberating against his Creator.¹¹⁴The word vayarev, generally translated as lay in wait, can also mean to argue or deliberate. He said: So said the Holy One blessed be He: “Go and smite Amalek…[put to death both men and women, infant and suckling babes, ox and sheep, camel and donkey” (I Samuel 15:3); if the men sinned, what sin did the women commit? What sin did the children commit? What sin did the cattle, the ox, and the donkey commit? A Divine Voice emerged and said: “Do not be overly righteous;” [do not be] more [righteous] than your Creator.
The Rabbis say: He began to deliberate regarding the beheaded calf and say: The verse said: “They shall behead the calf there in the valley” (Deuteronomy 21:4); he kills and it is beheaded?¹¹⁵The ritual of the beheaded calf is performed when a person is found dead between two cities and the killer is unknown. The elders of the nearest city perform this ritual, in which a calf is beheaded. Saul was uncomfortable with this ritual, arguing that a calf should not be killed because one person killed another. If a person sinned, what sin did the animal commit? A Divine Voice emerged and said: “Do not be overly righteous.”
Rabbi Shimon ben Lakish says: Anyone who becomes compassionate when he should be cruel will ultimately become cruel when he should be compassionate, as it is stated: “And Nov, the city of priests, he smote by sword” (I Samuel 22:19).¹¹⁶This was carried out at Saul’s command. Should Nov not be like descendants of Amalek? The Rabbis say: Anyone who becomes compassionate when he should be cruel, ultimately, the attribute of justice will harm him, as it is stated: “Saul and his three sons died” (I Samuel 31:6).

Nor overly wise. To deduce from a foolish inference from a minor case to a major case, [namely,] that for [the murder] of one person, said the Torah, bring a decapitated heifer, etc.⁴¹This Rashi refers back to the preceding one and explains the misdirected logic which led Shaul to spare Amoleik.