Withers

In Baldur's Gate 3, there is an npc that shows up in your camp that has a vested interest in your success. He has powers that aren't like normal characters, chief among them the ability to resurrect fallen allies. You could easily introduce a similar character into your campaign, maybe even the introduction to the campaign is this npc resurrecting the players.

This particular method has the benefit of being less nebulous than divine forces. It gives someone the players can interact with and someone that can give them direction. Whatever the reason they have for resurrecting your players, it's because they need their help.