“For I have come down from heaven, not to do My own will, but the will of Him who sent Me.” John 6:38 NASB
The Word came down from heaven, we are told, not to do His own will, but the will of Him who sent Him. Now, this shows that the will of the Father and of the Son, are not only so distinct as that each individually possesses the power to will, and can individually perform the act of willing, but also that what the Father and Son will is not identically the same.
For if the Father and Son did not have distinct operations of will, then the Son could not speak of His own will, and that Him that sent Him; for every action of willing would be identically one and the same, and so the Father willing something, and the Son willing something, could not be distinguished one from another, as they are here.
And if the content of each person’s will were identically the same, then the Son’s will and the Father’s will could not be distinguished. For the Son says that He came to do the will of Him Who sent Him, and not His own will. But if their wills were identically the same, this would be impossible; for doing what the Father willed, the Son would be equally doing what He Himself willed; and so, He could not say that He did the Father’s will but not His own. He can only have come to do the Father’s will and not His own, if their wills were not identically the same.
This then shows beyond a doubt that the Son has a distinct will from the Father. And such we should expect, since the Son is not the Father, but a distinct person from Him; not the one God, the Supreme Being, but a distinct individual being besides Him.
Yet the heretics, trying to get around the obvious and natural implication that the Father and Son are genuinely distinct individual beings (persons), not merely modes of the same person, vainly imagine that a single person can have multiple wills. This is something foreign to our experience in creation, foreign to the pages of scripture, and utterly contrary to sound reason. For if a single person had two wills, then how could they decide between which will to follow in a given instance? Do they have a third will also, to break the tie, and decide between the two? Or if what is meant is only that they have two distinct conflicting desires, how is this any different from what all men experience? Yet we do not on that account declare that we have two wills. The concept of a single person having two wills, then, is shown to have no merit; it being itself a seemingly incoherent notion, and beyond that, one which, more importantly, we lack any reason to believe in, from either anything in creation, or the scriptures.
Rather the scriptures would have us believe in God, and in His Son, and have eternal life in Them; not in one God in two names or modes, but in one God, and one only-begotten Son of that one God, two distinct persons (that is, two distinct rational individual beings). “This is eternal life, that they may know You, the only true God, and Jesus Christ whom You have sent.” (John 173 NASB).