tam tadrsakrtim viksya
mene dharmam saririnam
tasmai banam na muñcati
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
King Indra was fraudulently dressed as a sannyasi, having knotted his hair on his head and smeared ashes all over his body. Upon seeing such dress, the son of King Prthu considered Indra a religious man and pious sannyasi. Therefore he did not release his arrows.