Pure devotees of Lord are associates of Lord. To associate means to surrender unto them and surrender means to follow their instructions.
Prabhupada is showing us the way to return to the spiritual world. We just have to follow His instructions. Then we will reach our destination.
A general instruction of the spiritual master becomes a personal and specific instruction for a sincere disciple.
One must accept the words of an Acharya, a bona fide spiritual master, to clear the path for spiritual advancement. This is the secret of success. However, one’s guide must be a spiritual master who is actually an unalloyed devotee strictly following the instructions of the previous acharya without deviation. Whatever the spiritual master says must be accepted by the disciple. Only then is success certain. This is Vedic system.