Paladin subclass feature at level 7 for Oath of Redemption.

Base Effect

Starting at 7th level, you can shield others from harm at the cost of your own health. When a creature within 10 feet of you takes damage, you can use your reaction to magically take that damage, instead of that creature taking it. This feature doesn't transfer any other effects that might accompany the damage, and this damage can’t be reduced in any way.