Tertullian · a new plain-English translation from the original language
[1] So then, the main issue, and from it the whole engagement, concerns number: whether two gods may be admitted — or, if you like, by poetic and painterly license, even a third, a heretical one. But Christian truth has flatly declared: if God is not one, he is not at all — since we rightly believe that whatever is not what it ought to be, simply is not. [2] And to grasp that God must be one, pose the question of what God actually is, and you will arrive at no different answer. As far as the human condition can define God at all, I define him — and every conscience will recognize this too — as the supreme and great being, fixed in eternity — begotten by none, made by none, having neither a beginning nor an end. For this must be reckoned the very condition of eternity, which makes the supreme and great God what he is, since this quality is itself present in God; and so with everything else, so that God is supreme and great alike in form and in reason and in power and in might. [3] Since everyone agrees on this (for no one will deny that God is something supreme and great, unless he is prepared to declare, on the contrary, that God is something small and lowly — which is to deny God by stripping away what belongs to being God) — what, then, will be the condition of this supreme and great being? [4] Surely that nothing else be equal to him — that is, that there be no other supreme and great being; because if there were, he would be equaled, and if equaled, he would no longer be supreme and great, the very condition being overturned, and, so to speak, the law abolished that forbids anything to be equal to the supreme and great. [5] So it must be that whatever is supreme and great is unique, having no equal, or it would not be supreme and great at all. It cannot be otherwise than through the very thing by which it has its being, that is, by being altogether unique. Accordingly, since God is the supreme and great, our truth has rightly declared: if God is not one, he is not. Not that we doubt God exists, in saying 'if not one, he is not' — but because we are defining the very thing we are confident he is, namely: that if he is not this — supremely and greatly — he is not God at all. And the supreme and great, moreover, must necessarily be unique. Therefore God too will be unique: he is not God otherwise than as the supreme and great, and he is not the supreme and great otherwise than as having no equal, and he has no equal otherwise than by being unique. [6] Certainly, whatever other god you bring forward, you will be unable to maintain him as god in any other form than by ascribing to him too what is proper to divinity, eternity as much as supremacy and greatness. How, then, will two supreme and great beings coexist, when it belongs to the very nature of the supreme and great to have no equal — and having no equal is compatible only with being one, and could in no way apply to two?
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