What God communicates to the soul in this intimate union is totally beyond words. One can say nothing about it just as one can say nothing about God Himself that resembles Him. For in the transformation of the soul in God, it is God who communicates Himself with admirable glory. In this transformation, the two become one, as we would say of the window united with the ray of sunlight, or of the coal with the fire, or of the starlight with the light of the Sun. (1) ... The soul thereby becomes divine, becomes God, through participation, insofar as is possible in this life. ... The union wrought between the two natures, and the communication of the divine to the human in this state is such that even though neither changes their being, both appear to be God. (2)

(Saint John of the Cross)