The theme of Matthew Arnold's "Dover Beach" is the failure of religion in the modern world. It characterizes the Earth as a place that seems joyful and bright but is actually full of pain. Because religion can no longer soothe that pain, the speaker of the poem looks for consolation in romantic love.
The speaker of the poem begins beautifully, asking his lover to come to the window to see the glory of the sea at night and to feel the sweet night air. However, this image provokes a series of pessimistic thoughts. The ocean's sound, a "grating roar / Of pebbles," sounds an "eternal note of sadness." Linking this thought with those of the Greek playwright Aeschylus, the speaker then compares this darkened sea of night with religion, the metaphorical "Sea of Faith" that once encircled the whole planet in its bright embrace. However, in the night, the sea seems to retreat, leaving the world bereft of metaphysical comfort. The last stanza, like the first, is a request to his lover. However, now he begs for her love, "for the world, which seems / To lie before us like a land of dreams.../ Hath really neither joy,...Nor certitude, nor peace, nor help for pain." The speaker closes with a harrowing image, comparing life to a battle in which "ignorant armies clash by night," unaware of who is friend and who is foe. Religion's departure from the world leaves a dark place in which only personal relationships offer meaning or relief from pain.