Luke 1:31

And behold thou shalt conceive in thy womb,
&c.] Though a pure virgin, which never knew a man; and therefore, "a behold", is prefixed to it, as being what was extraordinary and wonderful; as it is also, in the prophesy of it, in ( Isaiah 7:14 ) to which the angel manifestly refers, and is, by Matthew cited, as accomplished hereby; (See Gill on Matthew 1:22) (See Gill on Matthew 1:23)

and bring forth a Son, and shalt call his name Jesus;
which signifies a "Saviour"; and a Saviour Christ is of God's appointing, providing and sending; and a very suitable one, being a spiritual Saviour, and a complete one, both able and willing to save to the uttermost all that believe in him; nor is there any other, nor salvation in any other: he is the Saviour of his people, whom the Father has given him, even of all the elect, whether of Jews or Gentiles; and of them from all their sins, and from all their enemies; and whom he saves with a spiritual and eternal salvation.