Venomous Smite

The next time you hit a creature with a melee weapon attack during the spell’s duration, your weapon glows with sinister purple energy, and the attack deals an extra 1d8 poison damage to the target. In addition, the target must make a Constitution saving throw or become poisoned. The target can repeat the saving throw at the end of each of its turns, ending the condition on a success. 

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the initial extra damage dealt by the attack increases by 1d8 for each slot