Aid

Level: 2

Casting Time: 1 action

Range: 30 feet

Duration: 8 hours

Your spell bolsters your allies with toughness and resolve. Choose up to three creatures within range. Each target's hit point maximum and current hit points increase by 5 for the duration.

At Higher Levels.

When you cast this spell using a spell slot of 3rd level or higher, a target's hit points increase by an additional 5 for each slot level above 2nd.

Source: PHB, page 211. Available in the SRD.