But while he thought on these things, behold, the 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 Ghost.
20. And while he was considering these things We see here how seasonably, and, as we would say, at the very point, the Lord usually aids his people. Hence too we infer that, when he appears not to observe our cares and distresses, we are still under his eye.
Christ's incarnation is mystery to be adored, not probed. The espousal to Joseph honored the marriage state and saved the virgin's credit; without it, the world would ask whether He was a harlot's son rather than a carpenter's. God guards the reputation of His children with jealous care.
AI summary
Commenting on Matthew 1:18-25
But while he thought on these things,.... While he was revolving them in his mind, considering what was most fit and proper to be done, whether to dismiss her publicly or privately; while he was consulting within himself the glory of God, the peace of his own conscience, and the credit of Mary, behold the Angel of the Lord appeared to him in a dream...