It has been mentioned in the Purana that with the worship of Lord Vishnu in various forms like in the form of Boar, the Man-Lion, the Dwarf or the Hayagrivadestruction all wicked beings takes place. It destroys the fear of fetters of death and all calamities of life. Agni states that salutation to the Boar grinds all the evils and effects of all sins and salutation to the Man-lion has the capacity to destroy all dangers and break down all their enemies.
Agni Purana states that uttering the name of Lord Vishnu frees the body from all kinds of diseases and sufferings. All bodily and mental diseases are cleansed by Vasudeva. All innumerable ailments are completely done away with one being struck by the disc of Hari. On the other hand the recitation of the names of Achyuta, Ananta and Govinda destroy all diseases and makes the body pure.
Lord Agni says that the poison of animate beings and inanimate objects, the artificial poison, that of teeth and nails, that of the sky, that of the spider and various other insects all these and various other dreadful poisons are destroyed by the recitation of the name of Janardana in an unabated manner. It is said that ominous planets, evil stars, the female goblins, Vetalas, Pischachas, the Gandharvas, the Yakshas, the Rakshasas, Shakuni, Putana and the other she-devils, the Vainayakas, Mukhmandins, the wily Revati, the old Revati, the evil planets called the Vriddhakas, the Matrigrahas are warded off with the recitation of the early life of Vishnu. As one recites the early life of Lord Vishnu all the evil agencies which try to harm the children are completely destroyed.
With the help of the Agni Purana, the Fire God has prayed to the Man-Lion form of Vishnu. He says that the all powerful Man-Lion should consume all the evil agencies that infest old age, boyhood and youth. He should take away all evils and bring about goodness in the world. On the other hand Agni has asked Janardana, the one who is identical with all, to destroy all diseases, the great portents, all the poisons, all the evil stars, the obnoxious creatures, the bad influences of the dangers of corn-fields such as fire.
The Fire-God narrates that Vishnu has the power to destroy all demons and the power to protect all quarters including the earth, the sky, the rear, the sides and the front. The very remembrance of Vishnu immediately dissipates all sins. Evils meet with suppression with the name of the Janradana.
Finally Agni concludes saying that recitation of Hari's name removes all miseries from ones life.