The Catechism in Questions & Answers

95. What references to the birth of Jesus are there in the Old Testament?

In the Old Testament we find, among other things, the promise of prophet Isaiah: “Behold, the virgin shall conceive and bear a Son, and shall call His name Immanuel” (Isaiah 7: 14).
The prophet Micah foretold the place of Jesus’ birth: “But you, Bethlehem Ephrathah, though you are little among the thousands of Judah, yet out of you shall come forth to Me the One to be Ruler in Israel, whose goings forth are from of old, from everlasting” (Micah 5: 2). Isaiah described Jesus with names that emphasise His uniqueness: “For unto us a Child is born, unto us a Son is given; and the government will be upon His shoulder, and His name will be called Wonderful, Counsellor, Mighty God, everlasting Father, Prince of Peace” (Isaiah 9: 6).

Immanuel (“God with us”): see Question 115.

“But when the fullness of the time had come, God sent forth His Son, born of a woman, born under the law.”
Galatians 4: 4
see also Question 4