But they ask for proof that God is present when invoked for the sanctification of what takes place. Whoever asks this should read again what was examined earlier. For the argument establishing that the power manifested to us through the flesh is truly divine also supports the present point. Once it has been shown that the One manifested in the flesh is God, revealing His nature through the miracles that took place, it has also been shown that He is present in what takes place at every occasion of invocation.
For just as everything that exists has some distinctive property by which its nature is known, so truth is distinctive of the divine nature. And He has promised that He will always be present with those who invoke Him, that He will be in the midst of those who believe, that He will remain in all, and that He will be with each one.
Therefore we need no further proof that God is present in what takes place. We believe that He is God because of the miracles themselves; we know that it is distinctive of divinity to have no fellowship with falsehood; and because the promise cannot be false, we do not doubt that what was promised is present. The invocation through prayer that precedes the divine dispensation provides further confirmation that what is being effected is accomplished by divine action.
For if, in the other kind of human generation, the impulses of the parents shape what is begotten by the power of God, as was said earlier, even when they do not invoke God through prayer—and if, apart from that power, their effort is ineffective and useless—how much more fully will the purpose be accomplished in the spiritual manner of birth, where God has promised to be present in what takes place and, as we believe, has placed power from Himself into the work, where our own moral choice is directed toward what is sought, and where the assistance that comes through prayer is duly joined to it? For those who pray to God that the sun may shine on them do nothing to hinder what will certainly take place; yet no one would say that the earnestness of those who pray is useless because they ask God for what will certainly happen. In the same way, those who are persuaded by the unfailing promise of the One who promised that grace is certainly present to those who are regenerated through this mystical dispensation either make some addition to the grace or, at least, do not turn away the grace that is already present.
For that He is certainly present is believed because the One who made the promise is God; and the testimony to His divinity comes through the miracles. Therefore, on every ground, there is no doubt that God is present.