CAIRO — The cease-fire between Hamas and Israel will go into effect Sunday at 8:30 a.m. local time, mediator Qatar announced Saturday, as families of hostages held in Gaza braced for news of loved ones, Palestinians prepared to receive freed detainees, and humanitarian groups rushed to set up a surge of aid.

Early Saturday morning, Israel’s Cabinet approved the deal for a ceasefire in Gaza that would release dozens of hostages and pause the 15-month war with Hamas, bringing the sides a step closer to ending their deadliest and most destructive fighting ever.