Srila Prabhupada is "Siksa Guru Extraordinaire." He was constantly instructing his disciples both in person and thru his books and correspondence. Beyond that, he taught as a true Acarya, thru his personal example. He was extremely humble. Here in this excerpt of a letter to his disciple, Paramananda, (June 17, 1970), he expresses his natural humility:
“You have rightly observed that I am simply trying to execute the order of my Spiritual Master. Whatever is being done it is not on account of my intelligence or endeavor because I am simply an instrument in the hands of my Spiritual Master. I do not know how far I have got the capacity to carry His order, but I may say that I have a sincere desire to do it.”
Then Prabhupada uses his own example of humility to instruct his disciple about the secret of developing love of Krishna:
“This is Parampara system. If a student tries to satisfy his immediate Acarya or the Spiritual Master, that is the only qualification for advancing in Krsna consciousness. This is explained in the Guruvastakam -- yasya prasadad bhagavata prasado.”
Prabhupada quotes the verse by Srila Visvanath Cakravarti Thakur that he taught his disciples to sing daily at mangal aratik:
yasya prasadad bhagavat-prasado
yasyaprasadan na gatih kuto pi
“By whose grace (the guru), the Lord’s grace is received.
Without whose grace, there is no shelter anywhere.”
The secret of how to get the blessings of Krishna, Prabhupada explains to Paramananda, is to take shelter of guru. There is no other way, no shortcut. And to take shelter of guru, the disciple must feel himself helpless. This is humility.