Historical Event
Brit Bein HaBetarim — Covenant Between the Parts
15 Nisan
God made the Brit Bein HaBetarim (Covenant Between the Parts) with Avraham, foretelling the Egyptian exile, the Exodus, and the inheritance of Eretz Yisrael (Bereishit 15; Rashi). The angels appeared to inform Avraham that a son would be born to Sarah.