And when Paul's sister's son heard of their lying in wait,.... Paul might have a sister living in Jerusalem; or this her son might be there on account of his studies; he might be a pupil to one of the doctors, by which means he might come at this secret, that such a number of men were in ambush, in order to take away his uncle's life: wherefore having got intelligence of it,
he went and entered into the castle; the Alexandrian copy reads, "the synagogue"; but Paul was not there, but in the castle of Antonia; the Ethiopic version renders it, "the prison"; though it is plain that he was not very closely confined, it was easy to have access to him; the reason might be, not only because he was a Roman, but because he was uncondemned, nor was any charge proved against him:
and told Paul; what he had heard, that such a number of men had entered into a conspiracy to take away his life, and lay in wait for him; and this was an instance both of duty and affection to his uncle, and worthy of imitation, whether it proceeded from natural relation, or from religion, or both.