"That is the best form of religion which performing one becomes elevated to devotional service of the Lord. Not religious formalities. One has to test by the result. Phalena paricīyate. You are Christian, I am Hindu, or he is Mohammedan. That's all right. You are very good, I am very good, he is very good. But what is the result of your following religion? Have you attained love of God? Simply I go the church, I go to temple, and I do all kinds of nonsense, I have no love for God, I have love for my māyā and I go simply..., that is useless. Religious principle means... It doesn't matter whether you are Hindu or Christian or Muslim or anything. It doesn't matter. Just see Bhāgavata. Sa vai puṁsāṁ paro dharmo. That sort of religion is nice, best, by which you can develop love of Godhead. It doesn't mention that 'This religion is best, that religion is best.' That religion is best which helps someone, the religionist, to develop love of God, Godhead. If you put to test all kinds of religion in this formula of Śrīmad-Bhāgavatam, you'll understand which religion is best. You haven't got to ask anybody. Simply by testing how much one has developed love of Godhead. How much one has learned to love Kṛṣṇa or God. If, following any type of religion, if you get this result, then you have performed your religious principle very nicely. This is the answer.
And what kind of love? Ahaitukī, without any cause. 'Oh, I love God because I want something from Him.' Generally, as they love God, distress, they want something. 'My dear Lord, I am very unhappy. Please help me.' That is also good. That is not bad. That is accepted in Bhagavad-gītā. But that is not pure love. Pure love means there is no reason. 'Why I am loving Kṛṣṇa? Oh, there is no reason. I love Kṛṣṇa. I want Kṛṣṇa.' This is love. Just like Caitanya Mahāprabhu says... 'Whatever you do, You are my Lord. I don't mind whether You put me into distress or You put me into happiness. Or if You don't help me in realizing You. It doesn't matter. Still, I love You. Whether I am going to hell or heaven, it doesn't matter. But I love You.' Just like Cowper said, 'England, with all thy fault, I love you.' This is love. This is material, crude (example). Ahaitukī apratihatā. Apratihatā means that business, 'I love Kṛṣṇa,' cannot be stopped. 'I could not love Kṛṣṇa because I was busy in doing this thing or that thing, or because...' So many reason we can put forward. No.
Love of Kṛṣṇa cannot be stopped by any material reason. That is love. Nobody can say that 'For this reason I could not love Kṛṣṇa.' There is no reason. There is no impediment for anyone. Any circumstances. So any religious principle which helps a person to love Kṛṣṇa and God, in that way, without any reason, without any impediment...
Just like flow of the river. There is no impediment in this world which can stop the flow of the river. Or the waves of the Pacific Ocean. There is no power in the material world which can stop the waves going on, going on, going on. You see? Similarly, that is the best type of religion. Now just see how Bhāgavata is liberal in the description of religion. Religion... You are religious, you are very pious man—how it will be tested? How much you have developed love of God. That's all. Without any reason, without any impediment. This is test of best religion."
(Srila Prabhupada Lecture, San Francisco, April 1, 1969)