“If the Holy Spirit is not a being, why then did Jesus in Matthew 28 say disciples are to be baptized in the name of the Father and of the Son and the Holy Spirit?”
The Holy Spirit is the omnipresence of the being of God Himself. “God is a Spirit: and they that worship him must worship him in spirit and in truth.” (John 4:24) Yet, as we read the Bible we find that the Holy Spirit is not a separate being from the Father and His Son, but rather the omnipresent Spirit of God, which is holy. “Whither shall I go from thy spirit? or whither shall I flee from thy presence?” (Psalms 139:7)
Regarding Matthew 28, Jesus was talking to His disciples when He said, “Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost.”(Matthew 28:19) Peter, who was a disciple of Jesus, was obviously present when Jesus gave this command. If we want to know what Jesus meant by this command, we can trust Peter to give us the proper understanding. Let’s turn to the text of Scripture where this command of Jesus was obeyed for the first time. In Acts chapter two Peter said, “Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost.” (Acts 2:38) Here Peter instructed these people to be baptized in the name of Jesus Christ, rather than in three separate names. But, supposing Peter temporarily forgot the command of Jesus, let us find more evidence.
In Acts chapter 10, Peter “commanded [Cornelius and his brethren] to be baptized in the name of the Lord.” (Acts 10:48) From these verses it is plain that Peter must have understood the command of Jesus differently than most Trinitarians understand it today. However, maybe Peter was alone in his understanding of this command.
When Peter and John came to Samaria they found a group of people who had been “baptized in the name of the Lord Jesus.” (Acts 8:16) Obviously Peter was not alone in his understanding of the command of Jesus.
What about Paul? Keep in mind that Paul said of the gospel he preached, “I neither received it of man, neither was I taught it, but by the revelation of Jesus Christ.” (Galatians 1:12) How did Jesus teach Paul to baptize?
When Paul visited Ephesus he met certain brethren there who had only been baptized by John’s baptism. Paul instructed them about Christ, and “when they heard this, they were baptized in the name of the Lord Jesus.” (Acts 19:5)
There is no record in the Bible of anyone baptizing in three separate names of three individual persons. Now there are three possibilities that could explain this. 1) The disciples were in direct rebellion against Jesus and purposely disobeyed His commandment. 2) The disciples understood the command of Jesus differently than most Trinitarians understand it today. 3) Jesus never gave the command to baptize “in the name of the Father, and of the Son, and of the Holy Ghost.”
The most logical and reasonable of these possibilities is choice number two. The disciples obviously understood the command of Jesus differently than most Trinitarians understand it today.
Let us look at it in another way. Jesus commissioned us to baptize in the name of the Father and of the Son, and of the Holy Spirit (Greek pneuma). Was Jesus, by making this commission, trying to teach the idea of a trinity? I think not, or He would have been contradicting other statements He made, and many statements made by other Bible writers. There is nothing in the verse that says there are three persons in the Godhead. There is nothing in the verse that says who is God. The word “God” is completely missing from the verse. We learn elsewhere in the Bible that the “one God” of the Bible is the Father. Paul wrote, “To us there is but one God, the Father, of whom are all things, and we in him; and one Lord Jesus Christ, by whom are all things, and we by him.” (1 Corinthians 8:6) The Bible uses the phrase, “God the Father” thirteen times, but it never says, “God the Son,” or “God the Holy Spirit.”
Notice also that the verse says we are to baptize in the name of… Why is it singular if there are supposed to be three persons? The word name in the Bible often refers to a person’s character. Jacob’s name was changed to Israel because his character had changed. If we believe this verse to be referring to actual names of three individuals, as most Trinitarians suppose, then it would be impossible to fulfill the command. The text says to baptize “in the name of…” Simply reciting the statement, “I baptize you in the name of the Father, and of the Son, and of the Holy Ghost” is not fulfilling the command. To baptize someone in the name of a person we must know the person’s name. It would be possible for us to baptize in the literal name of the Father, for we know His name: Yahweh or Jehovah. It would also be possible for us to baptize in the literal name of the Son, for we know His name: Yahshua or Jesus. But it is not possible for us to baptize someone in the literal name of the Holy Spirit, for nobody knows that name, if it exists.
The Father anointed His Son with His own Spirit. Therefore they have the same Spirit. “Thou hast loved righteousness, and hated iniquity; therefore God, even thy God, hath anointed thee with the oil of gladness above thy fellows.” (Hebrews 1:9) “For he whom God hath sent speaketh the words of God: for God giveth not the Spirit by measure unto him.” (John 3:34) As plainly shown, the Father has given His Son His Spirit. What type of spirit do they share? Surely, it is a Holy Spirit. The Bible mentions several different types of spirit. We read in the Bible about “foul spirit,” “evil spirit,” “unclean spirit,” “dumb spirit,” “excellent spirit,” “humble spirit,” “wounded spirit,” “broken spirit,” “haughty spirit,” “faithful spirit,” “good spirit.” All these spirits are distinguishable by the adjective that describes them. We know that God the Father has a spirit, and can that spirit be anything else, or anything less, than Holy? The word “Holy” is an adjective in every case, whether in English or in Greek. “Holy Spirit” is not a name, but a description of the Spirit of God.
Matthew 28:19 certainly does not prove a trinity, nor does it prove that the Holy Spirit is a separate being from the Father and His Son. If we are to find proof of these doctrines in the Bible we must look elsewhere.
I hope this helps to answer your question.