Catena Aurea on Mark 10:1–12: Augustine of Hippo

It makes nothing, however, to the truth of the fact, whether, as Matthew says, they themselves addressed to the Lord the question concerning the bill of divorcement, allowed to them by Moses, on our Lord’s forbidding the separation, and confirming His sentence from the law, or whether it was in answer to a question of His, that they said this concerning the command of Moses, as Mark here says. For His wish was to give them no reason why Moses permitted it, before they themselves had mentioned the fact; since then the wish of the parties speaking, which is what the words ought to express, is in either way shewn, there is no discrepancy, though there be a difference in the way of relating it. It may also be meant that, as Mark expresses it, the question put to them by the Lord, What did Moses command?, was in answer to those who had previously asked His opinion concerning the putting away of a wife. And when they had replied that Moses permitted them to write a bill of divorcement, and to put her away, His answer was concerning that same law, given by Moses, how God instituted the marriage of a male, and a female, saying those things which Matthew relates [Matt 19:4]; on hearing which they again rejoined what they had replied to Him when He first asked them, namely - Why then did Moses command?