Christian tradition has spent all these two thousand years defending that Jesus Christ is the only Son of God, incarnations of God, and one with God. This understanding has created a spiritual apartheid between Christ and Christians, between Christ and the rest of the humanity. May be it has served its purpose.In our time it is an outdated concept. I think it is right time now to abolish this spiritual apartheid and open the experience Jesus had to the whole of humanity.
Spiritual apartheid. That's a perfect way to describe this! I'm adding that to my vocabulary to express this separation of Jesus from humanity. But this understanding that Jesus is not the ONLY, mean numerically one Son of God is not modern. I just discovered this writing not long ago in Meister Eckhart following my own opening realization in meditation practice (it's always amazing how that happens). It follows perfectly with what you just said. Meister Eckhart of course was from the 14th Century, as I believe you know well as a Dominican, if I recall the order you are in correctly.
"The hearing of God’s Word requires complete self-surrender. He who hears and that which is heard are identical constituents of the eternal Word. What the eternal Father teaches is his own Being, Nature, and Godhead – which he is always revealing through his only begotten Son. He teaches that we are to be identical with him.
To deny one’s self is to be the only begotten Son of God and one who does so has for himself all the properties of that Son. All God’s acts are performed and his teachings conveyed through the Son, to the point that we should be his only begotten Son. And when this is accomplished in God’s sight, he is so fond of us and so fervent that he acts as if his divine Being might be shattered and he himself annihilated if the whole foundations of his Godhead were not revealed to us, together with his nature and being. God makes haste to do this, so that it may be ours as it is his. It is here that God finds joy and rapture in fulfillment and the person who is thus within God’s knowing and love becomes just what God himself is."
How powerfully true. The worst thing that happened historically for the Church is that theologically they took the Trinity formulation and made it a hard theistic definition of God. In doing this, they "kicked Jesus upstairs", as I've heard someone describe it. This created this spiritual apartheid, as you describe it. The Trinity is actually a Panentheistic view, one of transcendence and immanence paradoxically existing and realized within our own humanity, in the same way in which Jesus realized this. To become as Christ, is to become aware of our nature, and our identity, as the "only" begotten Son of God, as Eckhart says above.
Correct me if I'm wrong, but I believe the word "only" is actually better translated as "special" or "beloved". It is expressive of a mutuality of special relationship, not a numerical "one". All of us, to be as Christ, which the Apostle tells us to seek, is to in fact BE the Christ in us, in our uniqueness as individuals, One with God, as Jesus. To be like Christ, when realized in ourselves, means we too are the Son of God. How can this not be? It is our true Identity for us to realize and be.