Actually, the purpose of our life is to please Krsna. That is the business of the older children, to serve the father. So there is a test for knowing if I am pleasing Krsna: If He reveals Himself to me, if I see Krsna, then I know I am pleasing Krsna. And another test is if my spiritual master is pleased by my service then I know that I am pleasing Krsna. It is very simple, because if I am following the prescribed regulative principles of my spiritual master, then without doubt I am pleasing Him.

Srila Prabhupada — letter to Kirtiraja, Feb. 28, 1972