In "Dover Beach" Matthew Arnold does not just "suggest" a connection between present and past suffering; he spends the entire second stanza discussing the connection explicitly.
At the end of the first stanza, the narrator states that the sound of the tide brings in a note of "eternal sadness." In the second stanza, the narrator states that Sophocles heard this same note on the Aegean sea long ago and that the "ebb and flow" of the tide brought into Sophocles' mind the ebb and flow of human misery.
The sea connects the speaker with Sophocles physically, as there is no actual barrier between the Mediterranean and Atlantic. The water flows unimpeded between them. The sea also connects the speaker and Sophocles historically, as people in disparate periods still experience the same sea. Thus the sea is a case of something eternal and universal encompassing our world, and thus can work as a metaphor for notions of the divine.