Love* is the basis of real Christianity; but in practice Christianity is seldom real.
As I said yesterday, if we regard gnosticism as the replacement of love by knowledge, as the focus of Christianity; then this form of pseudo-Christianity has been and is usually dominant.
It is much easier to have a religion of knowledge than of love; and the less spiritual a society becomes - the more that this is the case. With knowledge at the centre; Christianity can become the subject of organisation - hierarchy and specialisation; of education and training, of initiation and ordination.
Churches often exclude, discipline and expelled people for inadequate or incorrect knowledge - but seldom or never for insufficient love; or for the opposite of love such as excessive fear, resentment or pride. Converts and aspirants are tested on their knowledge, not their love.
Christians, especially Christian leaders (and aspiring leaders), may falsely claim to be motivated by love. When asked for proof of love, people either suggest that it is wholly subjective, private and inaccessible - and therefore cannot or should not be judged and evaluated.
Or else (in trying to avoid such 'relativism') they invent 'proxy-measures of love', and thereby ignore the reality of love. Thus, people 'prove' their motivation-by-love, by (for example) doing impressive works of public charity, or performing extreme ascetic feats. In other words, but in a different way; they replace love with... knowledge... again.
What we can see is that any kind of institutional structure requires 'objective measures' and that real love is unsuitable to be such a measure. Therefore, any and every form of organisation is intrinsically gnostic.
(Of course, love and knowledge of love are two different things; a young child may love, but not know that he loves. Love may exist without knowledge. Nonetheless, Christianity can only be discussed if love can be known.)
It is a strange business and very different from the rest of life! For a Christian, love is not just real - but the reallest things of all; not just the proper focus of mortal life, but the actual basis of the creation of everything.
(Note: One who cannot love, cannot be a Christian - the implications of the two great commandments (to love God and neighbour) and the whole of the Fourth Gospel make that fact crystal clear. This formulation is seldom stated, perhaps because many people - unlike Jesus - have tried to make Christianity universal. Whether people actually exist who cannot love is a separate matter - but if they do exist, then they cannot be Christian, and could not have life everlasting - 'could not' simply because they would not follow Jesus through death to resurrection.)
And yet love is apparently not amenable to detection and measurement... and yet it actually is. Love is knowable, indeed for a Christian love must be knowable; because the alternative is that love is subject to unlimited self-deception and unbounded false assertion.
As so often, all this mystery and problem is a consequence of inappropriate abstraction. Because love is a matter of common sense and common experience - within the family situation.
We may know of another's love, when that is a spouse, parent, sibling, son or daughter... We know of another's love when we are in a loving situation. Indeed, such known-love is as certain as anything can be, it is (when present) the most powerful motivator in the world - leading to extreme, even ultimate, forms of self-sacrifice and self-abnegation.
But love is not open-endedly scaleable. We can know of love in a loving family situation, and some analogous family-like situation; but can know of love only in such situations.
Love is straightforwardly knowable, and indeed 'measurable', within the family situation; but becomes an insoluble problem - is made an insoluble problem - when we try to make love the focus of an institution, a legal system, a polity...
In this sense gnosticism is an unavoidable consequence of organisation.
*Love needs to be understood in a 'metaphysical' sense that includes 'creation'. It was Love that both motivated and enabled divine creation; love that enables creation both to have novelty and to cohere; to develop and evolve and remain aligned in purpose; love that enables many beings (each with free will, with 'agency') to participate in the unity of creation - and so on.