Joseph (peace be upon him), sold by his brothers and falsely accused, ended up in an Egyptian prison. Two other men were thrown in with him: one had served wine at the king's table, the other had baked his bread. Each had a strange dream and asked Joseph what it meant, because they could see he was a good man.
Before he explained their dreams, Joseph spoke to them about God. He told them that he had left the religion of people who did not believe, and followed the way of his fathers, Abraham, Isaac and Jacob (peace be upon them).
Then he asked them a question: “O my fellow-prisoners! Are divers lords better, or Allah the One, Almighty?” (Qur'an 12:39 · Pickthall). He explained that the names they worshipped were only names their fathers had made up.
After that he interpreted their dreams. One would serve the king again. The other would not live. (Qur'an 12:36-41)
The Torah tells the same prison scene in Genesis 40, with the cupbearer and the baker and their dreams. Joseph says, “Do not interpretations belong to God?” In both tellings, a prisoner with nothing points to the One.
Judaism
“HEAR, O ISRAEL: THE LORD OUR GOD, THE LORD IS ONE.”
Deuteronomy 6:4 · JPS 1917
The central sentence of Judaism is the Shema: “Hear, O Israel: the LORD our God, the LORD is One” (Deuteronomy 6:4). Jews say it morning and evening, and many hope it will be their last words. The Talmud tells how Rabbi Akiva, executed by the Romans, died saying the word eḥad, One (Berakhot 61b).
Maimonides' second principle of faith is that God is one, with a oneness unlike any other: not one of a pair, nor one like a body that has parts.
The Mishnah draws a lesson from oneness. A king stamps many coins from one seal and they all come out alike. God stamped every person with the seal of the first human, and not one is like another; and humanity began from one person so that no one could say there are many powers in heaven (Mishnah Sanhedrin 4:5).
Christianity
“Jesus answered, “The greatest is, ‘Hear, Israel, the Lord our God, the Lord is one:”
Mark 12:29 · WEB
Jesus was asked which commandment was the greatest. He answered by quoting the Shema: “Hear, Israel, the Lord our God, the Lord is one.” Christians are monotheists and say so in their creeds: “We believe in one God”.
Christians also believe that the one God is Father, Son and Holy Spirit, three persons in one being: the Trinity. They understand this as a statement about the inner life of the one God, not three gods. Many churches keep Trinity Sunday, the Sunday after Pentecost, and sing Reginald Heber's “Holy, Holy, Holy”, written for that day.
Islam
“If Allah had willed to choose a son, He could have chosen what He would of that which He hath created. Be He Glorified! He is Allah, the One, the Absolute.”
Qur'an 39:4 · Pickthall (1930)
Al-Wāḥid occurs many times in the Qur'an, often with al-Qahhār, the All-Prevailing: “The day when they come forth, nothing of them being hidden from Allah. Whose is the Sovereignty this day? It is Allah's, the One, the Almighty.” (40:16, Pickthall). Tawḥīd, the oneness of God, is the foundation of Islam.
The Ashʿarī theologians described God as one in His essence, in His attributes and in His acts. Nothing shares His being, nothing is like His qualities, and nothing acts beside Him.
Same and different
The Shema, the creed and the Shahāda all begin with one God, and Jesus quoted the Shema himself. All three faiths reject many gods. The real difference is the Trinity: Christians believe the one God is three persons; Jews and Muslims believe God's oneness rules that out. Each describes its belief in its own words.
schools / familiesRainbow barcodesUse a cheap diffraction grating or an old CD to look at a street light, a candle and a bulb. Each shows a different pattern. Talk about how astronomers read starlight the same way.
faith groups / schoolsThree ways of saying OneLearn the Shema, the opening of the Nicene Creed and Sūrat al-Ikhlāṣ, each from someone of that faith. Notice what they share and listen carefully to how each explains its differences.