'Jesus said: "Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by me." [joh 14], therefore only Jesus can bring salvation.':
Suggestion: Remind them of the following verse from the Gospel of John, in which Jesus clarifies His words by saying "As long as I am in the world, I am the light of the world." [joh 9:5] (6:24) see

Also explain the Oneness of the Prophets, the Manifestation as the Mediator between God and man, how Jesus was the Way during His dispensation and that it was actually the Holy Spirit speaking through Christ Who was saying He was the only way, but since the Holy Spirit reappears in each successive Manifestation, that Manifestation becomes the Way during His dispensation.
But also remember that Jesus also said:"Then spake Jesus again unto them, saying, I am the light of the world: he that followeth me shall not walk in darkness, but shall have the light of life.", so don't try to tell them that they are following the wrong Manifestation, which could start an argument and thus undo all the teaching you've done with them. [joh 8:12] (6:25) see

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