What happened after Abraham sent Hagar away?
After Abraham sent Hagar away, God intervened. In the desert, God went to Hagar and told her to go back to Sarah's tent and stay there. Thirteen years later, God told Hagar and Ishmael to go back where He brought her from, out in the desert.
Les explains that when Sarah could no longer tolerate Hagar's taunting, she told Abraham to get rid of her, and Abraham did send her away. But God intervened out in the desert. God went to Hagar and instructed her, "Hagar, you go right back to Sarah's tent, and you just stay there." Les points out that God knew that thirteen years later, He would tell Hagar and Ishmael to go right back where He brought her from in the first place, out in the desert. This connects to the Galatians 4 picture where the bondwoman and her son, representing the Law and legalism, are to be cast out.