John Chrysostom

And when he had considered the thing, he came to the house of Mary the mother of John, whose surname was Mark; where many were gathered together praying. Observe how Peter does not immediately withdraw, but first brings the good tidings to his friends.

And when he had considered, it says: viz. where he was, or, that he must not without more ado depart but requite his Benefactor: he came to the house of Mary the mother of John. Who is this John? Probably he that was always with them: for this is why he adds his distinctive name, "whose surname was Mark." But observe, "praying" in the night, how much they got by it: what a good thing affliction is; how wakeful it made them! Do you see how great the gain resulting from the death of Stephen? do you see how great the benefit accruing from this imprisonment? For it is not by taking vengeance upon those who wronged them that God shows the greatness of the Gospel: but in the wrong-doers themselves, without any harm happening to those, he shows what a mighty thing the afflictions in themselves are, that we may not seek in any wise deliverance from them, nor the avenging of our wrongs.

And when he had considered, he came to the house of Mary. Then let us not hide God's marvels, but for our own good let us study to display these abroad for the edifying of the others. For as he deserves to be admired for choosing to be put into bonds, so is he worthy of more admiration, that he withdrew not until he had reported all to his friends.