מדרש אויף משלי 23:24

These are the generations of Isaac, Abraham’s son: Abraham begot Isaac (Gen. 25:19). Scripture states elsewhere in allusion to this verse: The father of the righteous will greatly rejoice; and he that begetteth a wise child will have joy of him (Prov. 23:24). Concerning whom did Solomon make this statement? He said it about Isaac. When Isaac was born, the entire universe rejoiced; the heavens and the earth, the sun and the moon, the stars and the planets. Why did they rejoice? Because the world would not have survived had Isaac not been born, as it is said: If My covenant be not with day and night, if I have not appointed the ordinance of heaven and earth (Jer. 33:25). My covenant refers to Isaac, as it is said: I will establish My covenant with Isaac (Gen. 17:21).

[2] (Proverbs 23:24): "The father of the righteous will greatly rejoice, and he who sires a wise son will be glad in him" - Rabbi Ishmael said: Blessed is David, King of Israel, who merited to give birth to a wise son and to rejoice in his wisdom, therefore it is said "and he who sires a wise son will be glad in him." What is written after it - (Proverbs 23:25): "Let your father and your mother be glad" - Rabbi Akiva said: Even the Holy One, Blessed be He, and Wisdom rejoice in him: "Let your father" - this is the Holy One, Blessed be He; "and your mother" - this is Wisdom, as it is said (Proverbs 2:3): "For if you cry for discernment."

“This is the legacy of Isaac, Abraham’s son. Abraham begot Isaac” (Genesis 25:19).
“This is the legacy of Isaac, Abraham’s son.” “The father of the righteous will exult with happiness [gil yagil], and the begetter of the wise will rejoice in him” (Proverbs 23:24) – happiness [gila] after happiness when the righteous one is born. “It was in the days of Aḥaz…” (Isaiah 7:1) – Rabbi Hoshaya said: The ministering angels said before the Holy One blessed be He: ‘Master of the universe, woe that Aḥaz reigned.’¹Ahaz was a wicked king. See II Kings 16:1–4. He said to them: ‘He is Yotam’s son. His father was righteous, and I cannot extend my hand against him.’ “And the begetter of the wise will rejoice in him” – Rabbi Levi said: From where do you say that anyone who has a son who diligently engages in Torah, that he becomes filled with mercy upon him? The verse states: “My son, if your heart is wise, my heart too will rejoice” (Proverbs 23:15). Rabbi Shimon ben Menasya says: I have derived only the heart of his flesh and blood father, from where is it derived that even the Holy One blessed be He becomes filled with mercy upon him when he diligently engages in Torah? The verse states: “My heart too²The midrash is explaining that the verse says "too" as a reference to God, who rejoices with him. will rejoice.” Happiness after happiness – when he is a righteous one, son of a righteous one; “this is the legacy of Isaac, Abraham’s son.”