My house rule "fix" for the 1st-level feature "Emboldening Bond" 

You can forge an empowering bond among people who are at peace with one another. As an action, you choose a number of willing creatures within 30 feet of you (this can include yourself) equal to your proficiency bonus. You create a magical bond among them for 10 minutes, or until you lose your concentration (as if you were concentrating on a spell), or until you use this feature again. While any bonded creature is within 30 feet of another, the creature can roll a d4 and add the number rolled to an attack roll, an ability check, or a saving throw it makes. Each creature can add the d4 no more than once per turn. 

If a bonded creature reduces an enemy to 0 hit points with a melee or ranged attack, it can choose to incapacitate the foe, rather than deal a killing blow. The creature falls unconscious and is stable.

Dual concentration. You can concentrate on this feature and another spell that requires concentration, but if you lose your concentration, you lose both effects.

The issue with the feature not requiring concentration, as many have pointed out, is the potential abuse of stacking this effect at low level with bless or similar magical buff. This revised feature still allows for creative stacking effects, but limits it.

The "can choose to incapacitate the for, rather than deal a killing blow" fits the domain theme nicely.

In our games, I use this Dual Concentration rule for some other spells and effects: friends, water walk (which doesn't normally require concentration), alter self come to mind...