In John 12:41, the narrator of the Fourth Gospel remarks, “Isaiah said these things because he saw his glory and spoke of him.” There is no question that the referent of the pronouns “his” and “him” is Jesus. Similarly there is no ambiguity about the episode in which Isaiah “saw his glory”: it is the vision of Isaiah 6 in which the prophet sees the Lord “high and lifted up.” (The quotation from Isaiah 6 which immediately precedes this verse all but proves this.) John is making a simple exegetical point, with weighty theological ramifications: when Isaiah saw the Lord, the Lord he saw was Jesus, the Logos, the eternal Son, in his eternal heavenly glory.

(John also clearly believes that the “suffering servant” of Isaiah 53 is likewise Jesus; but that is a point upon which to expand another time.)

This helps to clarify what, from the trinitarian perspective of the New Testament (yes, I said it!), is the exact nature of the testamental discontinuity — and continuity. It is not that the Old Testament exclusively reveals the Father as God, while the Son is previously “unknown” as also being God. (A fortiori regarding the Spirit!) Neither, therefore, is it that God was known as One in the Old Covenant, and is now known as Three in the New, and these must somehow be reconciled by a complicated theological grammar. Rather, John’s remark implies that when the One God has been seen and heard and worshipped in the Old Covenant, it is as the eternal Son that He has been seen and heard and worshipped. The Logos is always characteristically the one who makes the invisible God visible — audible, perceptible, thinkable, knowable. (Consider John 1:18: “No one has ever seen God.") There is for John thus, at the divine level, an absolute continuity of both revelation and worship between the covenants. The discontinuity — and therefore the scandal — of the New Covenant is merely (!) that God the eternal Son is revealed and worshipped as a man: “the Logos became flesh and dwelt among us.” This is the scandal which is too great for the Pharisees in the passage to accept — “to whom has the arm of the Lord been revealed?”