But, brother, if thy fears be true, And this bright creature that we view Be fierce Márícha in disguise, Then by this hand he surely dies. For that dire fiend who spurns control With bloody hand and cruel soul, Has roamed this forest and dismayed The holiest saints who haunt the shade.

In plain words: Rama tells Lakshman that if his fear is right and the deer is really the demon Maricha in disguise, Rama will kill him. Maricha has long terrified the holy hermits of this forest.