Through your allies' exploits, you can attain victory even if you fall

Encounter ✦     Divine
Immediate Reaction      Close burst 10

Channel Divinity: You can use only one channel divinity power per encounter

Trigger: An enemy damages you

Target: One ally in the burst

Effect: The target gains 5 temporary hit points.
Level 11: 10 temporary hit points.
Level 21: 15 temporary hit points.

Published in Eberron Player's Guide, page(s) 93.