Tosefta for Nedarim 90:6

One who says to her husband, "The Heavens stand between me and you," he seeks a way to effect appeasement between them (Ned. 11:12), for thus we find regarding our Matriarch Sarah, that she said to our Patriarch Abraham (Gen 16:5), "Hashem will judge between me and you." Rather, thus she said to him (Gen. 21:10), "Expel this maidservant and her son." It teaches that our Matriarch Sarah saw Ishamael her (i.e., Hagar's) son building high places, and hunting locusts and offering them up and turning them to smoke for idol worship. She said, "Lest he teach Isaac my son to do thus, and he will go and worship thus, thereby desecrating the Name of Heaven by such things." He said to her, "After one bestows a benefit on a person, may he then disadvantage him (i.e., remove the benefit)? Thus, after we made her a queen, after we made her a lady, and brought her close to such greatness, shall we banish her from within our house? What will people say about us? Would not the Name of Heaven be desecrated by such a thing?" She said to him, "Since you say, 'This thing is a desecration of the Name,' let the Place decide between my words and your words." The Place decided between her words and his words, as it is said (Gen 21:12), "Everything (kol) that Sarah says to you, listen to her voice." Let the verse not say "everything" (i.e., since Sarah only made one request)! And why then does the verse say "everything"? It teaches that [God] was deciding a second time [between them], and [thus already] had decided a first time. Just as the second time was on account of Hagar, so too the first time was [also] on account of Hagar.