Actually there are three sets of readings this time around.

Isaiah 9:2-7; Psalm 96; Titus 2:11-14; Luke 2:1-20

Isaiah 62:6-12; Psalm 97; Titus 3:4-7; Luke 2:1-20

Isaiah 52:7-10; Psalm 98; Hebrews 1:1-12; John 1:1-14

As you can see the Luke narrative is included twice. Also note that the Wise Men narrative is not included. This will come several weeks later as part of Epiphany. The messianic prophesies are included in the Isaiah passages. I plan to post some devotional thoughts on Christmas day about these passages.