And she shall bring forth a son, and you shall call his name JESUS: for he shall save his people from their sins.
All Commentaries on Matthew 1:21 Go To Matthew 1
What the Angel thus told Joseph, was beyond human thought, and the law of nature, therefore he confirms his speech not only be revealing to him what was past, but also what was to come; “She shall bring forth a Son.”
Or, he left it unappropriated, to show that she bare Him to the whole world.
This further shows that this birth should be wonderful, because it is God that sends down His name from above by His Angel; and that not any name, but one which is a treasure of infinite good. Therefore also the Angel interprets it, suggesting good hope, and by this induces him to believe what was spoken. For we lean more easily to prosperous things, and yield our belief more readily to good fortune.
Let them approach to hear this, who ask, Who is He that Mary bare? “He shall save His people;” not any other man’s people; from what? “from their sins. "That it is God that forgives sins, if you do not believe the Christians so affirming, believe the infidels, or the Jews who say, “None can forgive sins but God only.”