Let all the nations be gathered together, and let the people be assembled: who among them can declare this, and shew us former things? let them bring forth their witnesses, that they may be justified: or let them hear, and say, It is truth.
Ye are my witnesses, saith the LORD, and my servant whom I have chosen: that ye may know and believe me, and understand that I am he: before me there was no God formed, neither shall there be after me.
The above are two oft-used prooftexts for monotheism.
Before concluding that they are absolutes, it is worth taking a look at similar statements from the ancient world. As these come from avowed polytheistic sourcs they make for most interesting reading indeed.
From the Sumerian world.
From the mountain of sunrise to the mountain of sunset,-Hymn to Enlil as the Ruling Deity of the Universe. Pritchard, Ancient Near Eastern Texts Relating to the Old Testament (ANET), 3rd ed. with supplement, pg. 576.
There is no (other) lord in the land, you alone are king,
Enlil, in all the lands there is no queen, your wife alone is queen.
Heaven - he [Enlil] alone is its prince, earth - he alone is its great one,-Hymn to Enlil, the All-Beneficent. ANET, pg. 575.
The Anunna - he is their exalted god,
When in his awesomeness he decrees the fates, no god dares look at him...
From the Ugaritic corpus.
I alone am the one who can be king over the gods,-Baal IV. vii 50-53.
Who can fatten gods and men,
Who can satisfy the multitudes of the earth!
From the Egyptian Magical Papyrii.
This is the Consecration for All Purposes: Spell to Helios
"I invoke You, the Greatest God, Eternal Lord, World Ruler, who are over the World and under the World, Mighty Ruler of the Sea, rising at Dawn, shining from the East for the Whole World, setting in the West. Come to me, Thou who risest from the Four Winds, benevolent and lucky Agathos Daimon, for whom Heaven has become the Processional Way. I call upon Your Holy and Great and Hidden Names which You rejoice to hear. The Earth flourished when You shone forth, and the Plants became fruitful when you laughed; the Animals begat their Young when You permitted. Give Glory and Honor and Favor and Fortune and Power to this, NN, Stone which I consecrate today (or to the Phylactery [charm] being consecrated) for [or in relation to] NN. I invoke You, the greatest in Heaven, E'I LANCHYCH AKARE'N BAL MISTHRE'N MARTA MATHATH LAILAM MOUSOUTHI SIETHO' BATHABATHI IATMO'N ALEI IABATH ABAO'TH SABAO'TH ADO'NAI, the Great God, ORSENOPHRE' ORGEATE'S TOTHORNATE'SA KRITHI BIO'THI IADMO' IATMO'MI METHIE'I LONCHOO' AKARE' BAL MINTHRE' BANE BAI(N)CHCHYCHCH OUPHRI NOTHEOUSI THRAI ARSIOUTH ERO'NERTHER, the Shining Helios, giving Light throughout the Whole World. You are the Great Serpent, Leader of all the Gods, who control the Beginning of Egypt and the End of the Whole Inhabited World, who mate in the Ocean, PSOI PHNOUTHI NINTHE'R. You are He who becomes Visible each Day and Sets in the Northwest of Heaven, and Rises in the Southeast.
In the 1st Hour You have the Form of a Cat; Your Name is PHARAKOUNE'TH. Give Glory and Favor to this Phylactery.
In the 2nd Hour You have the Form of a Dog; Your Name is SOUPHI. Give Strength and Honor to this Phylactery, or to this Stone, and to NN.
In the 3rd Hour You have the Form of a Serpent; Your Name is AMEKRANEBECHEO THO'YTH. Give Honor to the God NN.
In the 4th Hour You have the Form of a Scarab; Your Name is SENTHENIPS. Mightily strengthen this Phylactery in this Night, for the Work for which it is consecrated.
In the 5th Hour You have the Form of a Donkey; Your Name is ENPHANCHOUPH. Give Strength and Courage and Power to the God, NN.
In the 6th Hour You have the Form of a Lion; Your Name is BAI SOLBAI, the Ruler of Time. Give Success to this Phylactery and Glorious Victory.
In the 7th Hour You have the Form of a Goat; Your Name is OUMESTHO'TH. Give Sexual Charm to this Ring (or to this Phylactery, or to this Engraving).
In the 8th Hour You have the Form of a Bull; Your Name is DIATIPHE', who becomes visible everywhere. Let all Things done by the use of this Stone be accomplished.
In the 9th Hour You have the Form of a Falcon; Your Name is PHE'OUS PHO'OUTH, the Lotus Emerged From the Abyss. Give Success and Good Luck to this Phylactery.
In the 10th Hour You have the Form of a Baboon; Your Name is BESBYKI. [Prayer for gift omitted?]
In the 11th Hour You have the Form of an Ibis; Your Name is MOU RO'PH. Protect this great Phylactery for Lucky Use by NN, from this Present Day for All Time.
In the 12th Hour You have the Form of a Crocodile; Your Name is AERTHOE'. [Prayer for gift omitted?]
You who have set at Evening as an Old Man, who are over the World and under the World, Mighty Ruler of the Sea, hear my Voice in this Present Day, in this Night, in these Holy Hours, and let all done by this Stone, or for this Phylactery, be brought to fulfillment, and especially NN matter for which I consecrate It. Please, Lord KME'PH LOUTHEOUTH ORPHOICHE ORTILIBECHOUCH IERCHE ROUM IPERITAO' YAI! I conjure Earth and Heaven and Light and Darkness and the Great God who created All, SAROUSIN, You, Agathon Daimonion the Helper, to accomplish for me everything done by the Use of this Ring or Stone!"
When you complete the Consecration, say, "The one Zeus is Serapis!"
Moshe Weinfeld, in his book The Decalogue and the Recitation of "Shema": The Development of the Confessions, points out (pg. 128) that all these texts are hymnodal-liturgical, and that the Shema is confessional-liturgical.
On page 130 Weinfeld states that "there appears to be a deep connection between the definition of God as 'one'and the obligation to love him." He provides two passages from the Hebrew Bible which make the connection obvious.
And he said, Take now thy son, thine only son Isaac, whom thou lovest...
My dove, my undefiled is but one; she is the only one of her mother, she is the choice one of her that bare her...
-Song of Solomon 6:9.
If people know of other, similar statements, please share!