XVIII. (82) And similar to what has been previously said, is that passage which occurs in another place, "God spake once, and twice I have also heard the same."18 The expression "once" resembles the unmixed power, for the unmixed power is the unit, and the unit is the unmixed power; but the "twice" resembles the mixed power, for neither one nor the other is a simple thing, inasmuch as it admits of combination or of division. (83) God, therefore, utters unmixed units: for the word which he utters is not a beating of the air, being absolutely mingled with nothing else whatever, but it is incorporeal and naked, in no respect different from the unit. But we hear by the number two; (84) for the breath being sent from the dominant part of us through the artery called the trachea, is formed in the mouth by the tongue, as by a kind of workman, and being borne outward, and mingled with its kindred air, and having struck it thus harmoniously, completes the mixture of the two powers; for that which sounds together by a combination of different noises is at first adapted to a divisible duad, having one sharp and one flat tone: (85) very beautifully, therefore, did he oppose one just reason to the multitude of unjust reasons, less indeed in number, but superior in power, in order that the worse of the two might not, like a weight put in a scale, weigh down the other; but that, by the power of the weight of the better one in the opposite scale it might have its lightness detected, and so be weakened.