Mary Oliver:

That his methods are endlessly suggestive rather than demonstrative, and that their main attempt was to move the reader toward response rather than reflection, is perhaps another clue to the origin of Whitman’s power and purpose, and to the weight of the task. If it is true that he experienced a mystical state, or even stood in the singe of powerful mystical suggestion, … then he was both blessed and burdened-for he could make no adequate report of it. He could only summon, suggest, question, call, and plead. And Leaves of Grass is indeed a sermon, a manifesto, a utopian document, a social contract, a political statement, an invitation, to each of us, to change. All through the poem we feel Whitman’s persuading force, which is his sincerity; and we feel what the poem tries continually to be: the replication of a miracle.

Abraham Joshua Heschel:

“How can I repay unto the Lord all His bountiful dealings toward me?” (Ps. 116:12). How to answer the mystery that surrounds us, the ineffable that calls on our souls? This is, indeed, the universal theme of religion. The world is full of wonder. Who will answer? Who will care? Our reverence is no answer. The more deeply we revere the more clearly we realize the inadequacy of mere reverence. Is it enough to praise, to extol that which is beyond all praise? What is the worth of reverence? Faint are all our songs and praises. If we could only give away all we have, all we are. The only answer to the ineffable is a mode of living compatible with the ineffable.