Shema

(4) ה' אחד; seeing that He created all phenomena in this universe, celestial or terrestrial out of a total void, it is logically impossible for there to be another phenomenon representing an existence independent of Him. It also makes him basically different, unique, for all things created by Him are by definition potentially terminal, transient existences. He is absolutely unique in the world based on four basic raw materials, water, fire, earth, air. This idea appears to be hinted at in the letter ד=4 in the word אחד which is written larger than usual and the letter ע in the word שמע which is also written in larger than normal script, suggesting that we should use our eyes to take note of these concepts, the “testimony, עד” that this is so. This is why our sages said that we must draw out the word אחד when reciting it so as to give us time to reflect on the full meaning of the verse.

One who recites the Shema should make it heard to his ears, as it says, “Hear, O Israel, the Lord our God is One”—Make heard to your ear what your mouth says.