In other words, he was saying when you depend completely on Krishna and no longer rely on any material thing or formula as a backup, you have no longer any backup, just the mercy of Krishna, then you will actually be humble. So that was a wonderful explanation that he gave, and that stayed with me all these years because that is actually the foundation of humility in Krishna consciousness. And obviously Prabhupada was an example of that.
Nothing will save you except the mercy of Krishna.
Harivilas das: I remember going on a morning walk around the Bois de Boulogne in which there are some lakes, and I remember asking Prabhupada a question. I asked several questions, but one specific question was, “Srila Prabhupada, what does it mean to be humble?” And his answer was really incredible. He said, “Humility means that you are convinced beyond any doubt that there is nothing in this world, absolutely nothing in this world, not your money, not your family, not your fame, not your gun, not your education, nothing that will save you except the mercy of Krishna. When you are convinced like this, then you are humble.” And that explanation really impressed me.
Reference: Following Srila Prabhupada-A Chronological Series by Harivilasa Dasa