‘And to this agree the words of the prophets; as it is written,'
Then he supports Peter's case from the prophets, citing them as infallible Scripture (‘it is written'). The quotation, taken from Amos 9:11-12, is interesting in that it neither follows MT nor LXX, although being closer to LXX. But in fact discoveries at Qumran, where the Hebrew lying behind this quotation is paralleled (4 Q Flor Acts 1:11), suggest that James was using a differing Hebrew text than MT, or possibly a book of quotations in Hebrew (we tend to forget that they had to use what they had available, and to learn it by heart. There were no ‘authorised' pocket Bibles).