This week, the 15th week of the year, we’re reading from the Prophet Isaiah at Mass, an important Old Testament book, the most frequently referenced Old Testament source in the New Testament, after the psalms. We read it extensively during Advent, Lent and Easter, and in the daily prayers of the hours.

The book is not the work of just one man, Isaiah, writing in his own lifetime. Over two centuries, from 742-500 BC, other writers quoted, added to and expanded the prophet’s words, with their own interests and time in mind. It’s a book compiled over time as one generation after another found God speaking to them in this great prophet. 

In those centuries three crucial periods in Israel’s history occurred: the emergence of the kingdom of Judea after the destruction of the northern kingdom of Israel in 722 BC, the destruction of Jerusalem and the exile of its people ( 587-539 BC), and the call to renewed hope for the exiled community ( 537-500 BC). So, the Book of Isaiah teaches us, first of all,  that God is not found in just one time or place.

Fr. Carroll Stuhlmueller, CP, offers a helpful summary of the Book of Isaiah in the Catholic Study Bible. Isaiah means “God saves.” Isaiah found a saving God in the messy political maneuvering of his day. Those following him afterwards brought “innovative insights into older traditions as they saw God’s saving presence in their time.” Can we learn from Isaiah to see a saving God in our time too?

“First Isaiah (1-39 ) is absorbed in the role of Jerusalem and especially the Davidic dynasty. Second Isaiah (40-55) ignores the Davidic dynasty, except for 55:3, which mentions the temple only once in a disputed passage (44:28), and considers Jerusalem as principally a religious symbol. Third Isaiah (56-66 ) completely ignores the dynasty, and contemplates a new messianic kingdom.”  (Catholic Study Bible RG 288)

Human hands, human interests, human history, human weakness are at work in the Book of Isaiah at every stage of its compilation. They’re always at work. They always get our attention. 

But the book begins with an experience that’s key to it all. Isaiah experiences a vision of God in the temple which initiates his ministry (Isaiah 6): 

”The vision of the Lord enthroned in glory stamps an indelible character on Isaiah’s ministry and provides a key to the understanding of his message. The majesty, holiness and glory of the Lord took possession of his spirit and, at the same time, he gained a new awareness of human pettiness and sinfulness. The enormous abyss between God’s sovereign holiness and human sinfulness overwhelmed the prophet. Only the purifying coal of the seraphim could cleanse his lips and prepare him for acceptance of the call: “Here I am, send me!” ( Isaiah, Introduction, New American Bible)

Is the most important lesson to draw from this book this: go before God, a merciful God who saves, and be constantly refreshed by his presence? In the presence of God we learn what it means to be merciful and turn to create a merciful society in our time.