You should know the mantras given at the time of diksa are not simply mantras. It is Himself Krsna, Guru, Caitanya Mahaprabhu, and all these things. Also, there is some difference between the diksa mantras and the maha-mantra, Krsnas name. Krsna-nama is Himself the Supreme Personality of Godhead, Krsna. There is no difference between Krsna and krsna-nama. It is only due to the quality of our chanting that we do not realize this. Actually krsna-nama is Krsna, there is no difference at all. You should believe that you are chanting the name, not chanting, but you are serving Krsna and Krsna is there. Have a very strong belief in this. Then you can advance in your devotion. I think so many people cannot realize this, that, “When I am chanting, Krsna is coming, Krsna is there.” Ajamila also could not believe that when he chanted the name of Narayana, that all the sins went, all his sins had burned. He never believed this. But when at the time of death the Yamadutas came and the four Visnudutas came and there was a dialougue between them, the Visnudutas said that, “All his sins have gone away. Now he is pure, now he is qualified to go to Vaikuntha.” Then he thought, “Oh, I have overcome death and I am so qualified that I may go to Vaikuntha?” He never realized this before…