I said this in a thread about a potential convert before and I'll say it again, nearly every religion can provide evidence of mystics who meditated so well that they saw the light. Among occultists basically every faith or system is considered effective at achieving its spiritual aims, and "Theosis" or "Samadhi," the bliss of union with the Godhead, is a process as mechanically consistent and imitable as making a sandwich. Not that it's that easy, it requires decades of discipline and the ability to still the mind's movements into absolute nothingness in order to percieve the truth of things, it's just well attested enough in various faiths both old and new that they can treat it like a science.
But only Christianity has figures like St. Augustine who can converse with his mother on the lives of those in heaven and reach such heights of love and bliss in their conversation that that question is answered on the spot, saying "And when our conversation had brought us to the point where the very highest of physical sense and the most intense illumination of physical light seemed, in comparison with the sweetness of that life to come, not worthy of comparison, nor even omention, we lifted ourselves with a more ardent love toward the Selfsame, and we gradually passed through all the levels of bodily objects, and even through the heaven itself, where the sun and moon and stars shine on the earth. Indeed, we soared higher yet by an inner musing, speaking and marveling at thy works. And we came at last to our own minds and went beyond them, that we might climb as high as that region of unfailing plenty where thou feedest Israel forever with the food of truth, where life is that Wisdom by whom all things are made, both which have been and which are to be. Wisdom is not made, but is as she has been and forever shall be; for 'to have been' and 'to be hereafter' do not apply to her, but only 'to be,' because she is eternal and “to have been” and “to be hereafter” are not eternal. And while we were thus speaking and straining after her, we just barely touched her with the whole effort of our hearts. Then with a sigh, leaving the first fruits of the Spirit bound to that ecstasy, we returned to the sounds of our own tongue, where the spoken word had both beginning and end."
Only Christianity has figures like St. Thomas Aquinas who can construct an unparalleled masterpiece of theology and then one day get randomly struck by the light in the middle of mass and say "The end of my labors has come. All that I have written appears to be as so much straw after the things that have been revealed to me."
Only Christianity has figures like St. Teresa of Avila who didn't just work for Theosis, but after a certain point had it given to her with no effort on her own, saying "Then the cloud rises to heaven taking the soul with it, and begins to show it the features of the kingdom He has prepared for it. I do not know whether this is an accurate comparison, but in point of fact that is how it happens. In these raptures, the soul no longer seems to animate the body, its natural heat therefore is felt to diminish and it gradually gets cold, though with a feeling of very great joy and sweetness. Here there is no possibility of resisting. . . rapture is, as a rule, irresistible. Before you can be warned by a thought or help yourself in any way, it comes as a quick and violent shock; you see and feel this cloud, or this powerful eagle rising and bearing you up on its wings. You realize, I repeat, and indeed see that you are being carried away you know not where. . .We have to go willingly wherever we are carried, for in fact, we are being borne off whether we like it or not. In this emergency very often I should like to resist, and I exert all my strength to do so, especially at such times as I am in a public place, and very often when I am in private also, because I am afraid of delusions. Sometimes with a great struggle I have been able to do something against it. But it has been like fighting a great giant, and has left me utterly exhausted."
Perhaps this entire post reads as insane to you, the preaching of the Apostles on Pentecost seemed like drunken gibberish to those who heard it for the same reasons, but the more you research faith not just as a theory but as a practice, the more it's true ends are testified to not by figures of myth but of history. Spirituality is not just confined to theory, it is a living thing that masters of every faith have achieved bliss through and only in modern times has that fact been shoved to the side because modern minds cannot account for it in a purely rationalist worldview. But only the Holy Spirit can give these blessings freely as a gift to those who love him and love Jesus because the Holy Spirit is love itself. Not many will see God in their lives, but Jesus promises that everyone who trusts him will see him in their deaths.