It is not surprising that John is joyful for the faithfulness of his spiritual children to the truth. Probably, there is in the world no spiritual professor or instructor, who won’t be joyful of his spiritual children or his pupils for their faithfulness to what he learnt them. But indeed, Christianity is not a certain new doctrine, of which we could on one hand, learn, and with which on the other hand, could be studied...
It is not surprising that John is joyful for the faithfulness of his spiritual children to the truth. Probably, there is in the world no spiritual professor or instructor, who won’t be joyful of his spiritual children or his pupils for their faithfulness to what he learnt them. But indeed, Christianity is not a certain new doctrine, of which we could on one hand, learn, and with which on the other hand, could be studied, as the adepts study whatever positions of their doctrine. It is not accidentally for the description of the spiritual state of his spiritual children the apostle uses the verb "walk": in the Hebrew, and the Aramaic the corresponding word is also used in the meaning "to hold something" or "to follow something ". And in the Greek variant of his message, John uses the word, used again at the time of Aristotle to denote a leisurely philosophical conversation, during which gradually, step by step the interlocutors approach the truth.
Such conversations, moreover, were well known not only by the Greek philosophers, but also by the teachers of the Jewish traditional schools and academies. Well then: is the truth inaccessible? As something abstract, definitely not. As a concrete Kingdom brought to the world by a concrete Messiah - definitely yes. But the Kingdom is above all life, these very living relationships with God, with Christ, with the neighbors, which form the spiritual space of the Kingdom.
This is, as to say, the specifics of the Kingdom, all the rest which we can say of it, including also from the theological point of view, is rather abstraction. And we can live, or, in other words, indwell in the Kingdom - be in communion with God and men and experience this communion. Here is, such experience could have been probably called indwelling in the truth from the point of view of the Christian. Indeed, staying in the truth for the Christians is not faithfulness to the doctrine, but faithfulness to the Kingdom. And in the One, Who brought the Kingdom to the world. And thus it is a continuous communion, relationships constantly renewed and updated. It is in fact what is called life.