It seems straightforward enough: a husband could divorce his wife if he just gave her a 'certificate of divorce.' But Jesus saw something far deeper.
The religious leaders of Jesus' day had twisted the Mosaic Law concerning divorce. Deuteronomy 24:1 allowed for a 'bill of divorcement' in cases of 'some uncleanness.' However, the popular interpretation, especially championed by the school of Hillel, had reduced this to almost anything a husband disliked about his wife – even if he simply found another woman he preferred.
This turned a legal safeguard, intended to manage difficult situations and protect the woman in some way, into a license for casual dismissal. They focused on the external act of providing a document, believing that as long as they followed this procedure, they were in the clear with God.
Jesus, however, pulls back the curtain. He reveals that marriage isn't just a societal contract that can be easily dissolved by observing a legalistic loophole. It's a profound, God-ordained union, meant to be sacred and lasting.