The reduction of the universe to a single being, the expansion of a single being even to God, that is love.
This line is Hugo at his most intense and lyrical, describing love as both narrowing and expanding at the same time. One person becomes the whole world, and the whole world seems to point back to that person. In context, the novel treats love as a force that can redeem, but also a force that can overwhelm. The metaphor captures how love can make ordinary life feel sacred, almost religious. It can resonate with anyone who has felt their thoughts orbit one person so completely that everything else fades. At the same time, it hints at danger: when the universe becomes one being, you risk losing yourself. The quote is love as both miracle and risk.