Acts 5:20

This was done both for the encouragement of the disciples, and for the benefit and instruction of the others. And observe how the proceeding in the present instance is just the same as in what Christ Himself did. Namely, in His miracles though He does not let men see them in the act of being wrought, He furnishes the means whereby they may be apprised of the things wrought: thus, in His Resurrection, He did not let them see how He rose; in the water made wine, the guests do not see it done, for they have been drinking much, and the discernment He leaves to others. Just so in the present case, they do not see them in the act of being brought forth, but the proofs from which they might gather what had been done, they do see. And it was by night that the Angel put them forth. Why was this? Because in this way they were more believed than they would have been in the other.

He did not bring them away to benefit themselves thereby, but, "Stand," he says, "and speak in the temple to the people." But if the guards had put them out, as those thought, they would have fled, that is, supposing they had been induced to come out: and if those had put them forth, they would not have stood in the temple, but would have absconded. No one is so void of sense, as not at once to see this.