Matthew 1:25

Verse 25. Knew her not. The doctrine of the virginity of Mary before the birth of Jesus is a doctrine of the Scriptures, and very important to be believed. But the Scriptures do not affirm that she had no children afterwards. Indeed, all the accounts in the New Testament lead us to suppose that she had. See Barnes "Mt 13:55,56". The language here evidently implies that she lived as the wife of Joseph after the birth of Jesus. Her firstborn son. Her eldest son, or he that by the law had the privilege of birthright. This does not of necessity imply that she had other children; though it seems probable. It was the name given to the son which was first born, whether there were others or not.