Lord Krishna says to Uddhava: “Giving no attention to people who laugh in ridicule, forgetting the body and insensible to shame, one should fall prostrate on the ground and bow to all beings down even to the dog, the Chandala, the cow and the ass.” Doing prostrations to others makes a man humble. If he entertains Narayana Bhava also when he does prostrations, this will help him to realise that whatever he sees is God, that there is nothing but God, that the manifestation is the Virat aspect of Brahman. Doing prostrations to others with Narayana Bhava is a great help for developing devotion. Do mental prostration to a cow or an ass or a dog and feel that you are doing prostration to Lord Hari. All living creatures, all objects are forms of Hari only. Never forget this point.
There are six advantages in doing prostration. Do not do it like a drill. Do it gently with Bhava (feeling). Feel that you are prostrating actually before Lord Narayana or Siva. It must be a perfect Sashtanga Namskar. The body with six members, knees, forehead, shoulders, feet, chest, eyes, etc. should touch the ground. It removes egoism, infuses humility, produces Sama Drishti (equal vision). It fills the heart with Bhakti (devotion). It draws all the heart (Atma Vasya). It eventually leads to God-realisation. You must touch the feet of those for whom you offer your prostration be he a Mohammedan, Christian, Chandala or Barber. This removes jealousy, Ghrina (contempt for untouchables), hatred, ideas of inferiority and superiority. Glory to such a man who does prostration to all. He becomes Narayana quickly.
If you prostrate before some one and at the same time if you think or speak of his defects, it is only pure hypocrisy. It is of no good. It is not a mark of showing respect to a greater man.
Do not do Namaskar like a drill. Do it gently with Bhava (feeling). Feel you are prostrating actually before Lord Narayana or Siva. You must do a perfect Sashtanga Namaskar. Glory to such a man who does Namaskar with Bhava. He will become Narayana Himself.
(pgs. 157-159, Self-Knowldege)