The Pharisees were not looking for guidance. Matthew says they came "tempting him," that is, testing Him. Barnes explains the trap: "There was the more art in the captious question which they proposed, as at that time the people were very much divided on the subject." Followers of the teacher Hillel said a man could divorce his wife for any offence or dislike, while the school of Shammai allowed divorce only for adultery. Whichever side Jesus took, they expected Him to make enemies of the other. Gill adds that they asked "not for information, but with a view to reproach him," and that Jesus had already spoken against divorce except for fornication (Matthew 5:32), so they hoped to catch Him either contradicting Moses or contradicting Himself. Matthew Henry sums it up: they "were desirous of drawing something from Jesus which they might represent as contrary to the law of Moses."

Jesus did not pick a side in their debate. He answered with a question of His own, "Have ye not read...?", and took them back to creation (Matthew 19:4-5). He drew the conclusion plainly: "What therefore God hath joined together, let not man put asunder" (Matthew 19:6). When they pushed back with Moses (Matthew 19:7), He explained that Moses allowed divorce "because of the hardness of your hearts," but "from the beginning it was not so" (Matthew 19:8), and He named fornication as the only exception (Matthew 19:9). Barnes notes that Jesus answered "not from Hillel or Shammai, their teachers, but from Moses, and thus defeated their malice."

"Put away" translates apolusai, a verb meaning to release or send away, used here for divorce. "For every cause" is kata pasan aitian, "for any reason at all." The phrase is the heart of the trap, because it was the very point the rabbis argued over.

The Law of Moses allowed a man who found "some uncleanness" in his wife to "write her a bill of divorcement" (Deuteronomy 24:1). Gill explains how the two schools read this. The school of Shammai said a man could put away his wife only "in case of uncleanness," while the school of Hillel allowed it for very trifling things. Gill gives examples from their writings: spoiling her husband's food by over-roasting or over-salting it, or, as one teacher said, finding another woman more beautiful. Mark's account of the same question leaves out "for every cause" and asks simply whether it is lawful "to put away his wife" (Mark 10:2).

The Pharisees asked how much the law would let a man get away with. Jesus answered by asking what God intended. He moved the conversation from the rabbis' debate to the Creator's design, "from the beginning" (Matthew 19:4, 8). He does not let a trap set the terms. He goes beneath the question to God's own purpose.

Matthew Henry observes that cases about marriage have sometimes been perplexed, "not by the law of God, but by the lusts and follies of men." Barnes adds that Jesus answered honestly even though His answer was sure to offend one party: "when it was proper, Jesus answered questions without regard to consequences." God's truth about marriage was not shaped to win the crowd.