The answer is: Quietly divorce her

Matthew 1:19 - the option of divorce was available under the Law of Moses, Deut 24:1. Normally the circumstances would have to be made public and required witnesses to testify, hence Joseph wanted to do it "privily".

When Joseph discovered that Mary was pregnant, it must have been a shocking moment for him. Mary, his betrothed, was having a child that wasn't fathered by him. In typical Roman or Jewish culture of that time, his response was not only noble but was also in line with the regulations under Mosaic Law, which allowed for men to consider divorce amid such circumstances.

But who was Joseph, really? He’s often overshadowed by the remarkable full-beam spotlight on Mary and Jesus. Joseph is described as a just and righteous man. His desire to handle the situation quietly speaks volumes about his character. In a culture where public shame could have destroyed Mary's reputation, Joseph’s instinct was to protect her.

Furthermore, let's explore the cultural lens. The act of engagement in those times was taken seriously; it was as important as marriage itself. Torah law dictated that even a betrothal could only be broken formally. This means Joseph’s private plan was not only kind but required legal procedures.

Dig a bit deeper, and you’ll see some fascinating echoes in this story. There's a similarity between Joseph’s quiet righteousness and that of other biblical figures who faced unexpected pregnancies, like Sarah or Hannah, offering illustrations talking about divine intervention and destiny. Joseph’s decision to reconsider his initial plan after an angel's visit showcases not just obedience, but also an openness to shifting one’s understanding in light of divine purpose—a vital theme illustrated across biblical narratives. It's an amazing snapshot of love, faith, and compassion tightly woven into the very beginning of the Christmas story!