And were praying for praying, A.V. When he had considered; better, with Meyer and Alford, when he perceived it, viz. the truth of his deliverance. Mary the mother of John was aunt to Barnabas (Colossians 4:10).
If Paul and Barnabas were not in her house at the time (which there is no evidence that they were), it is likely that all the particulars of Peter's escape may have been communicated to Paul by John Mark, and by him repeated to Luke.
That they went to the house of Mary before their return seems certain from their taking Mark with them to Antioch (verse 25), possibly to deliver him from the danger Christians were in at Jerusalem at this time.