Vishnupurana 3.17.p7

3.17.p7

When the glorious Vishnu heard their prayers he emitted from his person an illusory form which he gave to the celestials and said. "This illusory form shall so deceive the Daityas, that being led astray from the path of the Vedas, they shall be slain; for all gods, demons and others, who shall transgress the authority of the Veda, shall perish by my prowess which I exercise for the preservation of the universe. Go then; be not afraid; this illusory form shall go before you. O celestials, it shall be of great service to you, this day".