Matthew
Matthew 19:9BSB·traditional attribution

Now I tell you that whoever divorces his wife, except for sexual immorality, and marries another woman commits adultery.”

John Calvin Reformed @genevareformer

9. But I say to you. Mark relates that this was spoken to the disciples apart, when they had come into the house; but Matthew, leaving out this circumstance, gives it as a part of the discourse, as the Evangelists frequently leave out some intermediate occurrence, because they reckon it enough to sum up the leading points.

John Gill Reformed Baptist @doctorgill

And I say unto you,.... To his disciples, when they were with him alone in the house, and asked him more particularly about the subject, concerning which he had been discoursing with the Pharisees, as Mark observes, Mar 10:10 when he said to them much the same things, he had delivered before in Mat 5:32 whosoever shall put away in his wife; separate her from...

Albert Barnes Presbyterian @notesbybarnes

Verse 9. And I say unto you. Emphasis should be laid here on the word I. This was the opinion of Jesus--this he proclaimed to be the law of his kingdom--this the command of God ever afterwards. Indulgence had been given by. the laws of Moses; but that indulgence was to cease, and the marriage relation to be brought back to its original intention.