John Calvin Commentary Matthew 1:20

"But when he thought on these things, behold, an angel of the Lord appeared unto him in a dream, saying, Joseph, thou son of David, fear not to take unto thee Mary thy wife: for that which is conceived in her is of the Holy Spirit." — Matthew 1:20 (ASV)

And while he was considering these things. We see here how timely, and, as we would say, at the critical moment, the Lord usually aids his people. From this, we also infer that when he does not appear to observe our cares and distresses, we are still under his eye. He may, indeed, hide himself and remain silent; but when our patience has been subjected to the trial, he will aid us at the time his own wisdom has selected. However slow or late his assistance may seem, it is for our benefit that it is delayed in this way.

The angel of the Lord appeared to him in a dream. This is one of two ordinary kinds of revelations mentioned in the book of Numbers, where the Lord speaks as follows:

If there be a prophet among you, I the Lord will make myself known unto him in a vision, and will speak unto him in a dream. My servant Moses is not so. With him will I speak mouth to mouth, even apparently, and not in dark speeches (Numbers 12:6–8).

But we must understand that dreams of this kind differ widely from natural dreams. They have a character of certainty engraved on them and are impressed with a divine seal, so that there is not the slightest doubt of their truth.

The dreams that men commonly have arise either from the thoughts of the day, from their natural temperament, from bodily indisposition, or from similar causes. In contrast, dreams that come from God are accompanied by the testimony of the Spirit, which puts beyond a doubt that it is God who speaks.

Son of David, fear not. This exhortation shows that Joseph was perplexed with the fear of sharing in his wife's criminality by tolerating her adultery. The angel removes his suspicion of guilt, with the aim of enabling him to live with his wife with a clear conscience.

The title Son of David was used on this occasion to elevate his mind to that lofty mystery, for he belonged to that family and was one of the surviving few,¹⁰² from whom the salvation promised to the world could proceed. When he heard the name of David, from whom he was descended, Joseph should have remembered that remarkable promise of God concerning the establishment of the kingdom, so that he would acknowledge that there was nothing new in what was now told him. In effect, the predictions of the prophets were brought forward by the angel to prepare Joseph's mind for receiving this present gift.

¹⁰² “Quia esset ex ea familia, et quidem superstes cum paucis;” — “;” — “d'autant qu'il estoit de cette famille, et mesmes que d'icelle il estoit quasi seul vivant, avec quelques autres en bien petit nombre;” — “because he was of that family, and even of that he was almost sole survivor, with some others in very small number.”;” — “because he was of that family, and even of that he was almost sole survivor, with some others in very small number.”