Acts 4:15

15. Commanded… out The apostles were directed to withdraw while their judges should hold consultation. It is not an unimportant, though in some sense an unanswerable question, how Luke obtained his information of what was said in privy council. There were many ways in which he might have obtained it, and there was some way in which he certainly did obtain it, since he here reports its substance to us. There may have been secret believers like Nicodemus in the council. Caiaphas, as above noted, knew John personally, (John 18:15,) and so report may have reached John through intermediates, and the Christians thus have been informed.