Matthew 1:23

The virgin [η π α ρ θ ε ν ο ς]. Note the demonstrative force of the article, pointing to a particular person. Not, some virgin or other.

They shall call [κ α λ ε σ ο υ σ ι ν]. In ver. 21, it is thou shalt call. The original of Isaiah (vii. 14) has she shall call; but Matthew generalized the singular into the plural, and quotes the prophecy in a form suited to its larger and final fulfilment : men shall call his name Immanuel, as they shall come to the practical knowledge that God will indeed dwell with men upon the earth.

Immanuel (Hebrew, God is with us). To protect and save. A comment is furnished by Isaiah 8:10, "Devise a device, but it shall come to naught; speak a word, but it shall not stand, for with us is God." Some suppose Isaiah embodied the purport of his message in the names of his children : Mahershalal - hash - baz (speed - prey), a warning of the coming of the fierce Assyrians; Shear - Jashub (a remnant shall return), a reminder of God's mercy to Israel in captivity, and Immanuel (God is with us), a promise of God's presence and succor. However this may be, the promise of the name is fulfilled in Jesus (compare "Lo, I am with you always," Matthew 28:20) by his helpful and saving presence with his people in their sorrow, their conflict with sin, and their struggle with death.