How did Matthew Arnold define poetry’s role in an age of weakening religious beliefs?

Matthew Arnold believed that in an age of "crumbling creeds," where traditional religious foundations were being undermined by modern thought, poetry would increasingly be required to take the place of religion.1

He argued that as society moved away from absolute beliefs, people would turn to poetry to interpret life, console them, and sustain them. Consequently, he defined poetry as "at bottom a criticism of life," provided that this criticism is conducted under the strict conditions of poetic truth and poetic beauty.1

To fulfill this vital role, Arnold insisted that readers must learn to distinguish the best poetry from the inferior by using the works of acknowledged masters as "touchstones." By steeping themselves in these masterpieces—which exemplify "high seriousness" and superiority of diction and movement—individuals could find the moral and intellectual "deliverance" necessary to navigate the complexities and spiritual discomfort of the modern world.21