Revatinandana Dasa : In an evening class Prabhupada mentioned that he’d received a letter saying that a God-brother of his had passed away. Prabhupada said that when he was living in Vrindavan as a vanaprastha, this God-brother had kindly written him a letter, reminding him that Srila Bhaktisiddhanta Sarasvati had wanted him to take sannyas and preach in the West. Prabhupada said, “I did not want to take sannyas, because materially it is a very difficult position. But I received that letter from my God-brother, and around the same time my Guru Maharaj appeared before me three times in dream. Each time he walked away from me, turned around, and beckoned me to follow.” These things prompted Prabhupada to take sannyas. He said, “In this way, my Guru Maharaj pulled me out of this material world.” When he said “pulled”, his voice got thick and two tears suddenly shot out of his eyes, as if they were squeezed out by a shudder of ecstasy, and went running down his cheeks. Everybody in the room was speechless. I was impressed with the intense feeling he had when his Guru Maharaj called him to take sannyas.
Reference: Memories-Anecdotes of a Modern-Day Saint by Siddhanta Dasa