מדרש אויף בראשית 20:2

Rabbi Joshua ben Ḳorchah said: Because of his love for her, (Pharaoh) wrote in her marriage document (giving her) all his wealth, whether in silver, or in gold, or in man-servants, or land, and he wrote (giving) her the land of Goshen for a possession. Therefore the children of Israel dwelt in the land of Goshen, in the land of their mother Sarah. He (also) wrote (giving) her Hagar, his daughter from a concubine, as her handmaid. And whence do we know that Hagar was the daughter of Pharaoh? Because it is said, "Now Sarai Abram's wife bare him no children; and she had an handmaid, an Egyptian, whose name was Hagar" (Gen. 16:1). Pharaoh rose up early in the morning confused because he had not approached her, and he sent and called Abraham, and said to him: Behold, Sarai thy wife is before thee, and all the deeds of her marriage contract are with her, take (her) and go, do not tarry in this land, as it is said, "Now therefore behold thy wife, take her, and go" (Gen. 12:19). "And Pharaoh gave men charge concerning him, and they sent him forth" (Gen. 12:20). And he had Abraham led so as to come to the land of Canaan. He sojourned in the land of the Philistines in order to be refreshed there. And he went away. And everything is foreseen by the Holy One, blessed be He, and Abimelech sent and took Sarah, thinking to raise up children from her, as it is said, "And Abimelech… sent, and took Sarah" (Gen. 20:2).

And Abimelech became impotent, and all the women of his house became barren, even || to the smallest insect (which also became) barren, as it is said, "For the Lord had fast closed up all the wombs of the house of Abimelech" (Gen. 20:18). And the angel Michael descended and drew his sword against him. Abimelech said to him: Is this a true judgment and a true sentence to slay me as long as I had no knowledge? "Wilt thou slay even a righteous nation?" (Gen. 20:4). He said unto him: "Restore the man's wife, for he is a prophet" (Gen. 20:7). "And he shall pray for thee, and thou shalt live" (ibid.).

Rabbi Levi said: Twice “go you [lekh lekha]” is written,¹⁶Here and in Genesis 22:2. but we do not know which is more dear, whether it is the second or the first. From what is written: “[Go you] to the land of Moriah” (Genesis 22:2), we see that the second is more beloved than the first.¹⁷In the second, God told him his destination.
Rabbi Yoḥanan said: “Go you, from your land” – from your district; “and from your birthplace” – this means your neighborhood; “and from your father’s house” – this means from your father’s household. Why did he not reveal it [his destination] to him? It was to make it more endearing to him, and to give him a reward for each and every stride. That is in accordance with the opinion of Rabbi Yoḥanan [elsewhere], as Rabbi Yoḥanan said: “He said: Take your son, your only one” (Genesis 20:2). He [Abraham] said to Him: ‘This one is the “only one” to his mother and that one is the “only one” to his mother.’¹⁸Both Isaac and Ishmael were the only sons of their respective mothers. He said to him: “Whom you love” (Genesis 22:2). He said to Him: ‘Are their partitions in the innards?’¹⁹Is there any limit on a father’s love for all his sons? He said to him: “Isaac” (Genesis 22:2). Why did He not reveal it to him [immediately]? It was to make it more endearing to him, and to give him a reward for each and every statement.
As Rav Huna said in the name of Rabbi Eliezer son of Rabbi Yosei HaGelili: The Holy One blessed be He withholds [information at first] and keeps the eyes of the righteous directed toward Him, and only then does he reveal to them the particulars of the matter. So: “to the land that I will show you”; “upon one of the mountains that I will say to you” (Genesis 22:2); “proclaim the proclamation that I speak to you” (Jonah 3:2); “Go out to the valley and I will speak to you there” (Ezekiel 3:22).