Charles Ellicott Commentary Matthew 1:19

"And Joseph her husband, being a righteous man, and not willing to make her a public example, was minded to put her away privily." — Matthew 1:19 (ASV)

Joseph her husband — The word was applied with strict accuracy from the moment of betrothal onward.

Being a just man... — The glimpse we are given into Joseph's character is one of remarkable tenderness and beauty. As a man conscious of being from the house of David and cherishing Messianic hopes, the news he heard must have seemed to blight those hopes entirely.

As a "righteous" man, he could not bring himself to marry one who appeared to have sinned in this way. Yet, love and pity prevented him from enforcing the full penalty of the law, which prescribed death by stoning for such an offense (Deuteronomy 22:21). He was also unwilling to break off the engagement publicly on the grounds of her apparent guilt.

The remaining alternative, made easier by the growing frequency of divorce, was to use a certificate of divorce. This document did not need to specify the exact reason for the separation, other than using vague language that implied disagreement (Matthew 19:3). In this way, the matter could be settled quietly, without public disgrace.

This certificate of divorce was just as necessary for a betrothed couple as it was for those who were fully married.