“As soon as Peter realized this,
He went to the house of Mary,
The mother of John,
Whose other name was Mark,
There many had gathered
And were praying.”
συνιδών τε ἦλθεν ἐπὶ τὴν οἰκίαν τῆς Μαρίας τῆς μητρὸς Ἰωάνου τοῦ ἐπικαλουμένου Μάρκου, οὗ ἦσαν ἱκανοὶ συνηθροισμένοι καὶ προσευχόμενοι.
The author of Acts indicated that as soon as Peter realized or comprehended (συνιδών τε) that he was free, he went (ἦλθεν) to the house (ἐπὶ τὴν οἰκίαν) of Mary (τῆς Μαρίας), the mother of John (τῆς μητρὸς Ἰωάνου), who was called by his other name (τοῦ ἐπικαλουμένου) Mark (Μάρκου). Many people (οὗ ἦσαν ἱκανοὶ) had gathered together (συνηθροισμένοι), where they were praying (καὶ προσευχόμενοι). Peter then went to the house of Mary, the mother of John, who was called Mark. Who is he? This John Mark will appear again with Saul and Barnabas later in this chapter 12:25. He would come up again in chapter 15:37. He may have been a disciple companion of Peter as mentioned in the I Peter, chapter 5:13. He may also have been a cousin of Barnabas. Traditionally, this John Mark was usually considered the author of the Gospel of Mark. He had both a Jewish (John) and Greek name (Mark), a lot like Simon Peter. Mary was his mother and she lived in a big house that may have been the place where the Last Supper took place. Other people had gathered there to pray for Peter. Was it still the middle of the night? There was no mention of the family of Peter. He knew where this house was and how to get there without any help. Where would you go if you escaped from prison?