"Dover Beach" was written in approximately 1851 and is about what the poet perceived to be the diminishing of Christian faith in England at that time. The poem describes the tide going out and retreating from the eponymous beach, and the tide symbolizes the aforementioned Christian faith. As the tide goes out, it pulls the pebbles on the beach with it, and as the waves lap back towards the beach, the water "fling[s]" those pebbles "up the high strand."

In this metaphor, the people of England are caught up in and left stranded by the diminishing of Christian faith. Just as the pebbles are flung "up the high strand," so, too, are the English people stranded without the comfort of the retreating Christian faith. Without this faith, which, the poet implies, is retreating as surely as the tide, people are isolated from one another, just as the pebbles are separated and flung in different directions by the retreating tide in the poem.

In 1851, England was in the midst of an industrial revolution, and many people, like Matthew Arnold, thought that this revolution was prioritizing profit and material progress above and to the detriment of traditional social, communal values. Indeed, the industrial revolution seemed to exacerbate the conditions of poverty and usher in a more selfish, individualistic ethos. This is why, in the poem, Arnold mourns for a diminishing Christian faith. He implies that the loss of this faith is synonymous with a loss of social cohesion, and thus he describes the retreating tide as sounding "an eternal note of sadness."