Musar על מגילה 20:24

This statement resolves a major problem that arises from Deut. 28,63: "And as G–d once delighted in making you prosperous and many, so will He now delight in causing you to perish and in wiping you out." Our sages wonder: How can one describe G–d as actually enjoying our misery? Do we not have repeated statements describing G–d's pain and discomfiture whenever the Jewish people undergo afflictions (Megillah 10b)? Rabbi Eliezer answers that it is not G–d Himself who delights in our misfortunes, but rather He causes others to. This answer is supported by the grammatical meaning of the word "Yassis," used by the Torah. If the Torah were to describe G–d's personal delight, it would have written “Yassos” instead. Rabbi Eliezer's answer is difficult, seeing the Torah states explicitly כן ישיש עליך ה' אלוקיך, which clearly means that He Himself derives pleasure from what is happening! Why then the strange combination of ישיש with עליך? We also find the wording שוש אשיש, meaning: "I will personally rejoice" (Isaiah 61,10). Hence we cannot explain the expression ישיש as meaning something other than deriving personal joy. We also have Deut. 30,9, in which after describing the penitence of the Jewish people, the Torah says of G–d: "He will once again delight in your well-being, etc," and the expression used is “La-ssus”. We must conclude that the construction Yassis, therefore can have two meanings. On occasion it is a Hiphil, transitive, and would mean making others rejoice, whereas on other occasions it is used intransitively and means to derive personal joy.