We see then the significance of Christ’s deity and humanity to lie in regard to his work of revelation and reconciliation. He who reveals God to man, and reconciles man to God, must be both God and man, truly and completely God, and truly and completely man. If the Son was to redeem the whole nature of man, he had to assume the whole nature of man; if in the Son man is to be gathered into the fellowship and life of God, it must be by one who is truly and completely God. Only he can be mediator who is himself the union of God and man, only he can be pontifex [‘bridge-maker’] who is himself the pons [‘bridge’]. (T. F. Torrance, “Incarnation,” 190)
Sorry JW’s, Mormons, Muslims, Higher Critics, Bahai, etc., etc. Salvation needs both prongs of the hypostatic union to be just that. If not, all of humanity is hopeless.
One point (of many) of note here is the relationship between reconciliation and revelation; Jesus is both at once, He reveals God to humanity, as He assumes Humanity into His life, bringing the necessary reconcilation — in order to know God (we have both ontology and epistemology dealt with in the person of Christ).