Sometimes in ISKCON we hear it said that our disciplic succession is a siksha disciplic succession, not a diksha disciplic succession, a disciplic succession based on instructions (siksha) not on initiation (diksha). But even though there is an exception of Gaura Kishore Das Babaji not being initiated by Bhaktivinode Thakur and only having a siksha relationship with him, this does change the fact that the majority of the guru/disciple
relationships in our line of succession are based of diksha (initiation) which automatically includes (siksha) instructions.
One danger of minimizing the importance of diksa (initiation) is that a devotee may think that he does not have to strictly follow the instructions of his initiating guru, that he can choose to instead accept someone else as his instructing guru and follow his instructions instead of his initiating guru's instructions.
So what is the proper understanding? For this we will turn to the predominating siksha guru (instructing spiritual master) for all ISKCON devotees, ISKCON's Founder-Acharya: His Divine A.C. Bhaktivedanta Swami Prabhupada, to see what he has authoritatively taught us in this regard. He stated as follows while giving a Bhagavad-gita lecture in Honolulu, USA on 4 July 1974:
"A śikṣā-guru who instructs against the instruction of the spiritual master (dīkṣā-guru), is not a śikṣā guru. He is a demon. Śikṣā-guru, dīkṣā-guru means... Sometimes a dīkṣā-guru is not present always. Therefore one can take learning, instruction, from an advanced devotee. That is called the śikṣā-guru. Śikṣā-guru does not mean he is speaking something against the teachings of the dīkṣā-guru. He is not a śikṣā-guru. He is a
rascal."
Srila Prabhupada has thus reconfirmed that one must always remain dedicated to carrying out the orders he has received from his initiating spiritual master. Any devotee whose instructions help him to follow his initiating guru's instructions can be be accepted as an instructing guru, not those who instruct him differently from the instructions of his initiating guru, who should be understood to be rascals.
Sankarshan Das Adhikari