May I suggest that human intimacy, that sacred, physical union ordained of God for a married couple, deals with a symbol that demands special sanctity.
Such an act of love between a man and a woman is—or certainly was ordained to be—a symbol of total union: union of their hearts, their hopes, their lives, their love, their family, their future, their everything. It is a symbol that we try to suggest in the temple with a word like seal.
The Prophet Joseph Smith once said we perhaps ought to render such a sacred bond as “welding”—that those united in matrimony and eternal families are “welded” together, inseparable if you will, to withstand the temptations of the adversary and the afflictions of mortality.
| Of Souls, Symbols, and Sacraments