I have discussed Matt 28:18-19, a common "proof-text" for the Trinity a few times on this blog (e.g., this response to the God Loves Mormons Website on the Trinity). The Bible's normative use of the phrase, "in the name of" refers to an action within the context of delegated authority, and in not all instances it is literally identified by "name." Here is a listing of all such examples of the phrase “in the name of” in the KJV (except Matt 28:19) that should be taken into account before extracting any theology from this text:
(Deut. 18:5 KJV) For the LORD thy God hath chosen him out of all thy tribes, to stand to minister in the name of the LORD, him and his sons for ever.
(Deut. 18:7 KJV) Then he shall minister in the name of the LORD his God, as all his brethren the Levites do, which stand there before the LORD.
(Deut. 18:20 KJV) But the prophet, which shall presume to speak a word in my name, which I have not commanded him to speak, or that shall speak in the name of other gods, even that prophet shall die.
(Deut. 18:22 KJV) When a prophet speaketh in the name of the LORD, if the thing follow not, nor come to pass, that is the thing which the LORD hath not spoken, but the prophet hath spoken it presumptuously: thou shalt not be afraid of him.
(Deut. 21:5 KJV) And the priests the sons of Levi shall come near; for them the LORD thy God hath chosen to minister unto him, and to bless in the name of the LORD; and by their word shall every controversy and every stroke be tried:
(Deut. 25:6 KJV) And it shall be, that the firstborn which she beareth shall succeed in the name of his brother which is dead, that his name be not put out of Israel.
(1 Sam. 17:45 KJV) Then said David to the Philistine, Thou comest to me with a sword, and with a spear, and with a shield: but I come to thee in the name of the LORD of hosts, the God of the armies of Israel, whom thou hast defied.
(1 Sam. 20:42 KJV) And Jonathan said to David, Go in peace, forasmuch as we have sworn both of us in the name of the LORD, saying, The LORD be between me and thee, and between my seed and thy seed for ever. And he arose and departed: and Jonathan went into the city.
(1 Sam. 25:9 KJV) And when David's young men came, they spake to Nabal according to all those words in the name of David, and ceased.
(2 Sam. 6:18 KJV) And as soon as David had made an end of offering burnt offerings and peace offerings, he blessed the people in the name of the LORD of hosts.
(1 Ki. 18:32 KJV) And with the stones he built an altar in the name of the LORD: and he made a trench about the altar, as great as would contain two measures of seed.
(1 Ki. 22:16 KJV) And the king said unto him, How many times shall I adjure thee that thou tell me nothing but that which is true in the name of the LORD?
(2 Ki. 2:24 KJV) And he turned back, and looked on them, and cursed them in the name of the LORD. And there came forth two she bears out of the wood, and tare forty and two children of them.
(1 Chr. 16:2 KJV) And when David had made an end of offering the burnt offerings and the peace offerings, he blessed the people in the name of the LORD.
(1 Chr. 21:19 KJV) And David went up at the saying of Gad, which he spake in the name of the LORD.
(2 Chr. 18:15 KJV) And the king said to him, How many times shall I adjure thee that thou say nothing but the truth to me in the name of the LORD?
(2 Chr. 33:18 KJV) Now the rest of the acts of Manasseh, and his prayer unto his God, and the words of the seers that spake to him in the name of the LORD God of Israel, behold, they are written in the book of the kings of Israel.
(Ezr. 5:1 KJV) Then the prophets, Haggai the prophet, and Zechariah the son of Iddo, prophesied unto the Jews that were in Judah and Jerusalem in the name of the God of Israel, even unto them.
(Est. 3:12 KJV) Then were the king's scribes called on the thirteenth day of the first month, and there was written according to all that Haman had commanded unto the king's lieutenants, and to the governors that were over every province, and to the rulers of every people of every province according to the writing thereof, and to every people after their language; in the name of king Ahasuerus was it written, and sealed with the king's ring.
(Ps. 20:5 KJV) We will rejoice in thy salvation, and in the name of our God we will set up our banners: the LORD fulfil all thy petitions.
(Ps. 118:10 KJV) All nations compassed me about: but in the name of the LORD will I destroy them.
(Ps. 118:11 KJV) They compassed me about; yea, they compassed me about: but in the name of the LORD I will destroy them.
(Ps. 118:12 KJV) They compassed me about like bees; they are quenched as the fire of thorns: for in the name of the LORD I will destroy them.
(Ps. 118:26 KJV) Blessed be he that cometh in the name of the LORD: we have blessed you out of the house of the LORD.
(Ps. 124:8 KJV) Our help is in the name of the LORD, who made heaven and earth.
(Ps. 129:8 KJV) Neither do they which go by say, The blessing of the LORD be upon you: we bless you in the name of the LORD.
(Isa. 50:10 KJV) Who is among you that feareth the LORD, that obeyeth the voice of his servant, that walketh in darkness, and hath no light? let him trust in the name of the LORD, and stay upon his God.
(Jer. 11:21 KJV) Therefore thus saith the LORD of the men of Anathoth, that seek thy life, saying, Prophesy not in the name of the LORD, that thou die not by our hand:
(Jer. 26:9 KJV) Why hast thou prophesied in the name of the LORD, saying, This house shall be like Shiloh, and this city shall be desolate without an inhabitant? And all the people were gathered against Jeremiah in the house of the LORD.
(Jer. 26:16 KJV) Then said the princes and all the people unto the priests and to the prophets; This man is not worthy to die: for he hath spoken to us in the name of the LORD our God.
(Jer. 26:20 KJV) And there was also a man that prophesied in the name of the LORD, Urijah the son of Shemaiah of Kirjathjearim, who prophesied against this city and against this land according to all the words of Jeremiah:
(Jer. 44:16 KJV) As for the word that thou hast spoken unto us in the name of the LORD, we will not hearken unto thee.
(Mic. 4:5 KJV) For all people will walk every one in the name of his god, and we will walk in the name of the LORD our God for ever and ever.
(Zeph. 3:12 KJV) I will also leave in the midst of thee an afflicted and poor people, and they shall trust in the name of the LORD.
(Zech. 13:3 KJV) And it shall come to pass, that when any shall yet prophesy, then his father and his mother that begat him shall say unto him, Thou shalt not live; for thou speakest lies in the name of the LORD: and his father and his mother that begat him shall thrust him through when he prophesieth.
(Matt. 10:41 KJV) He that receiveth a prophet in the name of a prophet shall receive a prophet's reward; and he that receiveth a righteous man in the name of a righteous man shall receive a righteous man's reward.
(Matt. 10:42 KJV) And whosoever shall give to drink unto one of these little ones a cup of cold water only in the name of a disciple, verily I say unto you, he shall in no wise lose his reward.
(Matt. 21:9 KJV) And the multitudes that went before, and that followed, cried, saying, Hosanna to the Son of David: Blessed is he that cometh in the name of the Lord; Hosanna in the highest.
(Matt. 23:39 KJV) For I say unto you, Ye shall not see me henceforth, till ye shall say, Blessed is he that cometh in the name of the Lord.
(Mk. 11:9 KJV) And they that went before, and they that followed, cried, saying, Hosanna; Blessed is he that cometh in the name of the Lord:
(Mk. 11:10 KJV) Blessed be the kingdom of our father David, that cometh in the name of the Lord: Hosanna in the highest.
(Lk. 13:35 KJV) Behold, your house is left unto you desolate: and verily I say unto you, Ye shall not see me, until the time come when ye shall say, Blessed is he that cometh in the name of the Lord.
(Lk. 19:38 KJV) Saying, Blessed be the King that cometh in the name of the Lord: peace in heaven, and glory in the highest.
(Jn. 3:18 KJV) He that believeth on him is not condemned: but he that believeth not is condemned already, because he hath not believed in the name of the only begotten Son of God.
(Jn. 12:13 KJV) Took branches of palm trees, and went forth to meet him, and cried, Hosanna: Blessed is the King of Israel that cometh in the name of the Lord.
(Acts 2:38 KJV) Then Peter said unto them, 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 3:6 KJV) Then Peter said, Silver and gold have I none; but such as I have give I thee: In the name of Jesus Christ of Nazareth rise up and walk.
(Acts 4:18 KJV) And they called them, and commanded them not to speak at all nor teach in the name of Jesus.
(Acts 5:40 KJV) And to him they agreed: and when they had called the apostles, and beaten them, they commanded that they should not speak in the name of Jesus, and let them go.
(Acts 8:16 KJV) (For as yet he was fallen upon none of them: only they were baptized in the name of the Lord Jesus.)
(Acts 9:27 KJV) But Barnabas took him, and brought him to the apostles, and declared unto them how he had seen the Lord in the way, and that he had spoken to him, and how he had preached boldly at Damascus in the name of Jesus.
(Acts 9:29 KJV) And he spake boldly in the name of the Lord Jesus, and disputed against the Grecians: but they went about to slay him.
(Acts 10:48 KJV) And he commanded them to be baptized in the name of the Lord. Then prayed they him to tarry certain days.
(Acts 16:18 KJV) And this did she many days. But Paul, being grieved, turned and said to the spirit, I command thee in the name of Jesus Christ to come out of her. And he came out the same hour.
(Acts 19:5 KJV) When they heard this, they were baptized in the name of the Lord Jesus.
(1 Cor. 1:13 KJV) Is Christ divided? was Paul crucified for you? or were ye baptized in the name of Paul?
(1 Cor. 5:4 KJV) In the name of our Lord Jesus Christ, when ye are gathered together, and my spirit, with the power of our Lord Jesus Christ,
(1 Cor. 6:11 KJV) And such were some of you: but ye are washed, but ye are sanctified, but ye are justified in the name of the Lord Jesus, and by the Spirit of our God.
(Eph. 5:20 KJV) Giving thanks always for all things unto God and the Father in the name of our Lord Jesus Christ;
(Col. 3:17 KJV) And whatsoever ye do in word or deed, do all in the name of the Lord Jesus, giving thanks to God and the Father by him.
(2 Thess. 3:6 KJV) Now we command you, brethren, in the name of our Lord Jesus Christ, that ye withdraw yourselves from every brother that walketh disorderly, and not after the tradition which he received of us.
(Jas. 5:10 KJV) Take, my brethren, the prophets, who have spoken in the name of the Lord, for an example of suffering affliction, and of patience.
(Jas. 5:14 KJV) Is any sick among you? let him call for the elders of the church; and let them pray over him, anointing him with oil in the name of the Lord: