Just as fire applied to gold removes any discoloration caused by traces of other metals, Lord Vishnu within the heart purifies the minds of the yogis.
A devotee is the friend not only of human society but of all living entities, for he sees all living entities as sons of the Supreme Personality of Godhead. He does not claim himself to be the only son of God and allow all others to be killed, thinking that they have no soul. This kind of philosophy is never advocated by a pure devotee of the Lord.
The whole world is full of violence and a devotee's first business is to stop this violence, including the unnecessary slaughter of animals.
By one's engaging in the processes of demigod worship, austerities, breath control, compassion, bathing in holy places, strict vows, charity, and chanting of various mantras, one's mind cannot attain the same absolute purification as that achieved when the unlimited Personality of Godhead appears within one's heart.