In keeping with John Donne’s highly philosophical bent, “The Good-Morrow” is as much a poem about knowledge as it is a poem about love. But it would be more accurate to say that the poem is, among other things, an investigation of the relationship between love and knowledge. To modern readers, these concepts might seem to make something of an odd couple, as we generally associate “love” with the corporeal side of things, and “knowledge” with the somewhat-more-immaterial realm of thought or the mind.
But the association between love (or rather, a specific kind of love) and knowledge has a long history, both within the Christian tradition in which Donne wrote, and in Greek philosophy, on which that later tradition drew. The ancient Greeks had four different words we might translate as “love”: agape, eros, philia, and storge. Each of these terms denotes a specific kind, or aspect, of what we might call love: philia generally refers to friendship or affection, storge to instinctual or “natural” love, such as the love of a parent towards their child, eros—from which the modern term “erotic” is derived—to desire, lust, or romantic love, and agape to non-romantic, disinterested, ideal love.
Socrates, the philosopher immortalized by Plato, emphasized heavily the philia (love) that forms the first half of the term philosophy (literally, “the love of knowledge”). The implication was that the proper pursuit of knowledge lies in ‘loving’ it. Saint Augustine (354-430 AD), generally considered to be the father of the Christian theological and philosophical tradition, further developed this association between knowledge and love, and adapted it to Christianity, by identifying God with truth (in Latin, veritas), thereby identifying the love of God with the love of the truth.
The term agape also came to occupy a significant place in Christian theology. In the New Testament, most famously in John 3:13 but elsewhere as well, agape is the original word for “love” used in the phrase that the New International Version renders as “For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life.” Thus, in Christian thought, agape came to mean specifically the bond of love between humans, God, and Christ—the love of God for humankind, as well as the specific kind of love Christians are meant to have for that God, and the kind of love referred to in the injunction to “love thy neighbor.”
One can argue that Donne, in “The Good-Morrow,” draws on both of these related conceptions of love. His reference to the “Seven Sleepers den” is an allusion to the story of seven persecuted Christians who, while hiding in a cave, were barricaded in by the Romans, only to emerge, miraculously, alive and well centuries later. This parable appears to dramatize the phrase quoted above, God’s promise that “whoever believes in him shall not perish but have eternal life.” Their love (agape) for God, expressed by their unwavering commitment to their faith, sustained them. We can also note how little Donne’s short poem has in common with the straightforward expressions of desire (eros) that characterize so many love poems. Donne's speaker instead chooses to emphasize the way in which his love for the poem’s addressee re-shapes his experience—his way of seeing and knowing, the world.