Lily of the valley is steeped in legend. Some believe the small flowers actually formed from Eve's tears as she left the Garden of Eden, and the flower is mentioned several times in the Bible
Lily of the valley has represented different things across the centuries. In the Victorian era, it symbolized a return to happiness. In ancient times it was associated with humility and purity, as well as the goddess Ostara (from whose name we get our modern Easter). It's also been associated with the Greek god Apollo, who is said to have created it so his nymphs would have a soft carpet to walk on. In contemporary times it is associated with motherhood and happiness, but most formally with spring, especially May.
When the Bible refers to lilies, it's not talking specifically about Convallaria majalis. In fact, it's possible that the Bible is not even referring to more traditional types of lillies. Because flower names have changed so much over the years, and because different translations often compound confusion, it's difficult, if not impossible to know for certain which specific flowers are being referred to, and at one point "lily" was a name that simply meant a showy flower.
Convallaria majalis, in fact, was named lily of the valley at some point in the 16th or 17th century as a reference to Song of Solomon 2:1-2, which reads "I am a rose of Sharon, a lily of the valleys. / As a lily among brambles, so is my love among the young women." But that's not the only time the word lily appears in the Bible.
Matthew 6:28 has, perhaps, the most famous reference to lilies. It reads: "Consider the lilies of the field, how they grow / they toil not, neither do they spin." That same phrase, "lilies of the field" appears in Luke 12:27. The Songs of Solomon have a number of references to lilies. In 5:13 it reads: "His cheeks are like a bed of balsam, / Banks of sweet-scented herbs; / His lips are lilies / Dripping with liquid myrrh." In 4:5 it reads "Thy two breasts are like two young roes that are twins, which feed among the lilies." and in 7:2: "Thy navel is like a round goblet, which wanteth not liquor: thy belly is like an heap of wheat set about with lilies."
cited from: https://www.countryliving.com/gardening/a41229643/lily-of-the-valley-meaning-symbolism/ written by Christipher Michel, Published Sep 16, 2022.