This is a Rage Power option.
You can channel divine fury into your weapon strikes.
- While you're raging, the first creature you hit on each of your turns with a weapon attack takes extra damage equal to 1d6 + your proficiency bonus. The extra damage is necrotic or radiant; you choose the type of damage when you gain this feature.
- Additionally, the divine power that fuels your rage can protect you. If you fail a saving throw while you're raging, you can reroll it, and you must use the new roll. You can use this ability only once per rage.