The Religion and Philosophy of the Veda and Upanishads v1.c17.s1.27

v1.c17.s1.27

The slaying of Vṛtra is not merely attributed to Indra: by the syncretism of the Veda, it is also attributed to Agni and Soma. The gods as a whole are supposed to aid Indra in the contest, but at the roaring or hissing of the serpent they fled, leaving the Maruts only to aid him, and once at least even they fled, and left him alone. Viṣṇu is also an aider in the struggle and even earthly priests lend aid.