Chant

By means of the chant spell, the priest brings special favor upon himself and his party, and causes harm to his enemies. The spell requires intense concentration and therefore should the caster move, take any action, bonus actions, or reactions their concentration ends.
Beginning on your next turn, all those in the area of effect who are friendly to the Cleric gain +1 bonus to attack, damage and saving throws, while those of the priest's enemies suffer -1 penalties.
This bonus/penalty continues for up to 24 hours or as long as the caster continues to chant the mystic syllables.

However, should the caster cease chanting for an reason (silence spell or loses concentration) the spell ends immediately.  Multiple chants are not cumulative.