The Trinity is supported by the Hebrew Tanakh

I begin with Genesis 1:26-27 "Elohim" is plural based on the plural verb "asah" prefixed by the nun (1). This is also used among other languages towards pagan gods (2). Based on the Ugaritic texts, this is further proven (3). The Hebrew word for "revealed" is plural in Gen. 35:14 (4). Other plural references of Elohim are found (5). The word "Echad" in Hebrew is a compound unity. Here are the list of occurences in which Echad (highlighted blue in the pic) is used to imply plurality (6). Note the Hebrew "Yachid" is never used of God's oneness. Gen. 3:22 says Deut. 6:4 says: More plural references to God include:Psalm 149:2 "Let Israel be glad in his Maker; let the children of Zion rejoice in their King! "A commentator noted this:"Literally the Hebrew here brings forward the mystic doctrine of the Trinity, for it reads, "Let Israel rejoice in God his Makers. " --Simon de Muis (7)Job 35:10 also has "makers" (8)Isaiah 54:5"For your Creator will be your husband; the LORD of Heaven's Armies is his name! He is your Redeemer, the Holy One of Israel, the God of all the earth. "Isaiah 51:22" Thus says your Lord,The Lord and your God,Who pleads the cause of His people:"See, I have taken out of your handThe cup of trembling,The dregs of the cup of My fury;You shall no longer drink it. "These passages in Hebrew translated literally have the plural word "Makers" (9). Young's literal translation, a literal translation of the Hebrew reads"Remember also thy Creators in days of thy youth, While that the evil days come not, Nor the years have arrived, that thou sayest, `I have no pleasure in them. ' (10). Some propose that the plural of majesty is the proper interpretation of Elohim in plural references of Scripture, but scholars say otherwise:"Every one who is acquainted with the rudiments of the Hebrew and Chaldee languages, must know that God, in the holy Writings, very often spoke of Himself in the plural. The passages are numerous, in which, instead of a grammatical agreement between the subject and predicate, we meet with a construction, which some modern grammarians, who possess more of the so-called philosophical than of the real knowledge of the Oriental languages, call a pluralis excellentiae. This helps them out of every apparent difficulty. Such a pluralis excellentiae was, however, a thing unknown to Moses and the prophets. Pharaoh, Nebuchadnezzar, David, and all the other kings, throughout TeNaKh (the Law, the Prophets, and the Hagiographa) speak in the singular, and not as modern kings in the plural. They do not say we, but I, command; as in Gen. xli. 41; Dan. iii. 29; Ezra i. 2, etc. " (11)"This first person plural can hardly be a mere editorial or royal plural that refers to the speaker alone, for no such usage is demonstrable anywhere else in biblical Hebrew. Therefore, we must face the question of who are included in this "us" and "our. " It could hardly include the angels in consultation with God, for nowhere is it ever stated that man was created in the image of angels, only of God. Verse 27 then affirms: "and God [Elohim] created man in His own image, in the image of God he created him; male and female He created them" (NASB). God--the same God who spoke of Himself in the plural--now states that He created man in His image. In other words, the plural equals the singular. This can only be understood in terms of the Trinitarian nature of God. The one true God subsists in three Persons, Persons who are able to confer with one another and carry their plans into action together--without ceasing to be one God. " (12)"The best answer that they [Old Hebrew lexicographers and grammarians] could give was that the plural form used for the name (or title) of God was the 'pluralis majestatis,' that is the plural of majesty. .. to say nothing of the fact that it is not at all certain that the 'pluralis majestatis' is ever found in the Old Testament, there is an explanation much nearer at hand and much simpler, and that is, that a plural name was used for the one God, in spite of the intense monotheism of the Jews, because there is a plurality of person in the one Godhead. " (13)"Another very popular view in modem times is that God uses the plural, just as kings do, as a mark of dignity (the so-called "plural of majesty"), but it is only late in Jewish history that such a form of speech occurs, and then it is used by Persian and Greek rulers (Esdr. iv. 18; 1 Mace. x. 19). Nor can the plural be regarded as merely indicating the way in which God summons Himself to energy, for the use of the language is against this (Gen. ii. 18; Is. xxxiii. 10). " (14)Judaism:Zohar says this of the Trinity: ". . . the exalted Shechinah comprehends the Three highest Sephiroth; of Him (God) it is said, (Ps. 62:10) "God hath spoken once; twice have I heard this. " Once and twice means the Three exalted Sephiroth, of whom it is said: Once, once, and once; that is, Three united in One. This is the mystery. " (15)"Here is the secret of two names combined which are completed by a third and become one again. ‘And God said Let us make Man. ’ It is written, ‘The secret of the Lord is to them that fear him’ (Psalm 25:14). That most reverend Elder opened an exposition of this verse by saying ‘Simeon Simeon, who is it that said: "Let us make man? " Who is this Elohim? ’ With these words the most reverend Elder vanished before anyone saw him . .. Truly now is the time to expound this mystery, because certainly there is here a mystery which hitherto it was not permitted to divulge, but now we perceive that permission is given. ’ He then proceeded: ‘We must picture a king who wanted several buildings to be erected, and who had an architect in his service who did nothing save with his consent. The king is the supernal wisdom above, the Central Column being the king below: Elohim is the architect above . .. and Elohim is also the architect below, being as such the Divine Presence (Shekinah) of the lower world. ’ (16)Some say that the son of God is a Christian insertion, however in the DSS fragment 4Q246, it reads:"He shall be called the Son of the God; they will call him the Son of the Most High. .. He will judge the earth in righteousness. .. and every nation will bow down to him. .. with (God's) help he will make war, and. .. [God] will give all the peoples into his power. "Rabbinical Judaism has been admitted to have re-interpreted the plural reference to Elohim as one singular God (17). "Hear, 0 Israel, Adonai Eloheinu Adonai is one. These three are one. How can the three Names be one? Only through the perception of faith: in the vision of the Holy Spirit, in the beholding of the hidden eye alone! The mystery of the audible voice is similar to this, for though it is one yet it consists of three elements-fire, air and water, which have, however, become one in the mystery of the voice. Even so it is with the mystery of the threefold Divine manifestations designated by Adonai Eloheinu Adonai - three modes which yet form one unity. This is the significance of the voice which man produces in the act of unification, when his intent is to unify all, from the Infinite (Ein Sof) to the end of creation. This is the daily unification, the secret of which has been revealed in the holy spirit. " (18). The targums are aramaic translations and interpretations in the synagogues of how the Scriptures were originally to be understood. This is from Targum Neofiti"In the beginning, with wisdom, the Son of YHWH created the heavens and the earth" (19)Who are the persons implied in the plural name of God? in the LXX (one of the oldest O. T manuscripts) has this reading in which Jesus quotes this about himself:Psalm 110:3"With thee is dominion in the day of thy power, in the splendours of thy saints: I have begotten thee from the womb before the morning. "I ran out of characters, so i will adress later points on the identity of the plural persons in Elohim later. Sources:1. Glinert Modern Hebrew: An Essential Grammar Routledge p14 section 13 "(b)Agreement of verbs Verbs agree with their subject, and not only in gender and number but also in person. Present tense verbs distinguish masculine from feminine and singular from plural:"2. . http://books.google.com...3. K. van der Toorn, Bob Becking, Pieter Willem van der Horst (eds), Dictionary of deities and demons in the Bible (revised 2nd edition, Brill, 1999) ISBN 90-04-11119-0, p. 274, 352-34. NET Bible with Companion CD-ROM W. Hall Harris, 3rd, none - 2003 - "35:14 So Jacob set up a sacred stone pillar in the place where God spoke with him.30 He poured out a 20tn Heb "revealed themselves. " The verb iVl] (niglu), translated "revealed himself," is plural, even though one expects the singular"5. Haggai and Malachi p36 Herbert Wolf - 1976 If both the noun and the verb are plural, the construction can refer to a person, just as the statement "God revealed Himself" in Genesis 35:7 has a plural noun and verb. But since the word God, "Elohim," is plural in form,8 the verb . .. "6. . http://www.blueletterbible.org...;7. . http://www.spurgeon.org......8. . http://www.studylight.org......9. . http://books.google.com......10. . http://www.biblestudytools.com......11. Rabbi Tzvi Nassi, Oxford University professor, The Great Mystery, 1970, p612. Encyclopedia of Bible Difficulties, Gleason Archer, p.359, commenting on whether Gen 1:26 is a "plural of majesty"13. The God of the Bible, R. A. Torrey, 1923, p 6414. Trinity, A Catholic Dictionary, William E. Addis & Thomas Arnold, 1960, p 822-83015. Rabbi Simeon ben Jochai, The Propositions of the Zohar, cap. 38; Amsterdam edition, 11316. Zohar. Vol 1. Soncino Press edition.17. . http://books.google.com.au......18. Zohar (III, 43b)19. Shepherd, Michael B. "Targums, the New Testament, and Biblical Theology of the Messiah. " JETS. 51:1 (2008), 45-58