As I point out elsewhere, Catholics are far more familiar with the Scriptures than we realize.
So much of the seasonal liturgies as well as the three-year cycle of readings is drawn directly from the Old Testament and the New Testament. In fact, more than forty passages from Isaiah are quoted or alluded to in more than fifty passages of the New Testament (LeClerc, Introduction to the Prophets, 186).
We are soon to begin a new liturgical year, and Advent-Christmas readings include beloved passages of Isaiah:
The nations come to Zion (2:2-4)
2 In the last days the mountain of the LORD’s temple will be established as the highest of the mountains; it will be exalted above the hills, and all nations will stream to it. 3 Many peoples will come and say, “Come, let us go up to the mountain of the LORD, to the temple of the God of Jacob. He will teach us his ways, so that we may walk in his paths.” The law will go out from Zion, the word of the LORD from Jerusalem. 4 He will judge between the nations and will settle disputes for many peoples. They will beat their swords into plowshares and their spears into pruning hooks. Nation will not take up sword against nation, nor will they train for war anymore.
A virgin shall conceive (7:10-14)
10 Again the LORD spoke to Ahaz, 11 “Ask the LORD your God for a sign, whether in the deepest depths or in the highest heights.” 12 But Ahaz said, “I will not ask; I will not put the LORD to the test.” 13 Then Isaiah said, “Hear now, you house of David! Is it not enough to try the patience of humans? Will you try the patience of my God also? 14 Therefore the Lord himself will give you a sign: The virgin will conceive and give birth to a son, and will call him Immanuel.
Unto us a child is born (9:1-6)
1 Nevertheless, there will be no more gloom for those who were in distress. In the past he humbled the land of Zebulun and the land of Naphtali, but in the future he will honor Galilee of the nations, by the Way of the Sea, beyond the Jordan— 2 The people walking in darkness have seen a great light; on those living in the land of deep darkness a light has dawned. 3 You have enlarged the nation and increased their joy; they rejoice before you as people rejoice at the harvest, as warriors rejoice when dividing the plunder. 4 For as in the day of Midian’s defeat, you have shattered the yoke that burdens them, the bar across their shoulders, the rod of their oppressor. 5 Every warrior’s boot used in battle and every garment rolled in blood will be destined for burning, will be fuel for the fire. 6 For to us a child is born, to us a son is given, and the government will be on his shoulders. And he will be called Wonderful Counselor, Mighty God, Everlasting Father, Prince of Peace.
The peaceable kingdom (11:1-10)
1 A shoot will come up from the stump of Jesse; from his roots a Branch will bear fruit. 2 The Spirit of the LORD will rest on him— the Spirit of wisdom and of understanding, the Spirit of counsel and of might, the Spirit of the knowledge and fear of the LORD— 3 and he will delight in the fear of the LORD. He will not judge by what he sees with his eyes, or decide by what he hears with his ears; 4 but with righteousness he will judge the needy, with justice he will give decisions for the poor of the earth. He will strike the earth with the rod of his mouth; with the breath of his lips he will slay the wicked. 5 Righteousness will be his belt and faithfulness the sash around his waist. 6 The wolf will live with the lamb, the leopard will lie down with the goat, the calf and the lion and the yearling together; and a little child will lead them. 7 The cow will feed with the bear, their young will lie down together, and the lion will eat straw like the ox. 8 The infant will play near the cobra’s den, and the young child will put its hand into the viper’s nest. 9They will neither harm nor destroy on all my holy mountain, for the earth will be filled with the knowledge of the LORD as the waters cover the sea. 10 In that day the Root of Jesse will stand as a banner for the peoples; the nations will rally to him, and his resting place will be glorious.