Here is the answer, and position we take on Matthews 3 at the Lord Jesus Baptism.
this is a little long, I tried to condense it. this is from my personal notes on the subject.
"the voice from heaven is this the Father's voice?". who told us that that it was. the bible never said it was the Father's voice, it said "A Voice", and the misunderstanding came in on an ASSUMPTION. many wanting to believe so hard in the three person, until they ERROR in assuming, it must be the Father's voice by what was said. this is not only a spiritual ERROR, but a big one.... never add or take away from the word of God. scripture, Matthew 3:17 "And lo a voice from heaven, saying, This is my beloved Son, in whom I am well pleased." many wrongly and willing make this mistake. oh yes, it's a easy mistake to make, (for we all are human, and make mistakes)... here, we call this the "ASSUMPTION" mistake. lets examine this verse and it's implications.
first things first. in studying the bible, ... "WITH THE HOLY SPIRIT" .... he will guide US in all TRUTH. and here in this setting we need his guidance. in Hermeneutics there is a section of study called the "NEAR and FAR Application". meaning what happen before, (near), will happen again in the Future, (Far) in similar application. and here, (at the Lord Jesus baptism), is a good example of this. so let the HOLY Spirit lead us.
so "A" voice from heaven spoke, but was it God's Voice? the bible do not say, only "A VOICE", lets see in scripture when a Voice from heaven is speaking on God's behalf. the book of Genesis, God told Abraham to sacrifice his only Begotten Son... do we see any similarities here at the Lord Jesus baptism? .... "only Begotten Son". (Near, Abraham only begotten Son, and Far, God's only begotten Son) so God told Abraham to sacrifice his only Begotten Son, and when Abraham was about to do it, what happen, well let the bible tell us. Genesis 22:10 "And Abraham stretched forth his hand, and took the knife to slay his son." Genesis 22:11 "And the angel of the LORD called unto him out of heaven, and said, Abraham, Abraham: and he said, Here am I." Genesis 22:12 "And he said, Lay not thine hand upon the lad, neither do thou any thing unto him: for now I know that thou fearest God, seeing thou hast not withheld thy son, thine only son from me." HOLD IT, STOP THE PRESS, what did the angel say? listen, "seeing thou hast not withheld thy son, thine only son from me". wait a second, the angel never commanded Abraham to sacrifice his ... ONLY BEGOTTEN SON... no, God did. but is was the angel speaking from ... "heaven" on God's behalf. the verse clearly states it was the angel ... "VOICE" from heaven that spoke.
never assume anything..... KNOW. and if the bible never say it was the Father's Voice, then don't ASSUME, and ADD to God's Holy Word, because that's spiritual suicide and the road to destruction,,,, so never, ever ASSUME anything, let the bible tell you. lets go on. " Genesis 22:13 "And Abraham lifted up his eyes, and looked, and behold behind him a ram caught in a thicket by his horns: and Abraham went and took the ram, and offered him up for a burnt offering in the stead of his son." Genesis 22:14 "And Abraham called the name of that place Jehovahjireh: as it is said to this day, In the mount of the LORD it shall be seen."Genesis 22:15 "And the angel of the LORD called unto Abraham out of heaven the second time," (WHERE DID THE ANGEL VOICE COME FROM? ... THAT'S RIGHT HEAVEN). Genesis 22:16 "And said, By myself have I sworn, saith the LORD, for because thou hast done this thing, and hast not withheld thy son, thine only son:" (WAS THIS GOD SPEAKING OR THE ANGEL, the ANGEL, on GOD'S BEHALF?). Genesis 22:17 "That in blessing I will bless thee, and in multiplying I will multiply thy seed as the stars of the heaven, and as the sand which is upon the sea shore; and thy seed shall possess the gate of his enemies;" Genesis 22:18 "And in thy seed shall all the nations of the earth be blessed; because thou hast obeyed my voice.", when was this command, and WHO spoke to Abraham in this command? answer, Genesis 22:1 "And it came to pass after these things, that God did tempt Abraham, and said unto him, Abraham: and he said, Behold, here I am." Genesis 22:2 "And he said, Take now thy son, thine only son Isaac, whom thou lovest, and get thee into the land of Moriah; and offer him there for a burnt offering upon one of the mountains which I will tell thee of."
so we can see that "a Voice" from heaven is not nessary always God's VOICE, but conveys his "WORDS". so never assume anything unless the bible say so. for if we did not have the actual speaker from heaven identified, here in Genesis 22 we could ... "ASSUME" by the words spoken that it is the Father's voice. so by the guidance of the Holy Spirit we will not make this mistake of "ASSUMPTION". for when the Bible say a Voice, then we say a voice unless we're told who voice it is, (and the bible never did, not at the Lord Jesus baptism). so this MISTAKE of ASSUMPTION is corrected and exposed for what it is, a false ASSUMPTION.
hope this helped,
PICJAG, 101G.