How to write religious sympathy messages
A religious sympathy message offers comfort through shared faith: a prayer for peace, a reminder of God's presence, or hope of being reunited. The most comforting ones are short and gentle. Grief makes reading hard, so two or three sentences are plenty.
Only use faith-based language if you know the person shares it; otherwise a simple "thinking of you" message is kinder. If you knew the person who died, add a short memory of them. And if you can, offer something practical: a meal, a ride, or simply your presence.