gather ye rosebuds while ye may

The first line of the poem “To the Virgins, to Make Much of Time,” from the middle of the seventeenth century, by the English poet Robert Herrick. He is advising people to take advantage of life while they are young:

Gather ye rosebuds while ye may,
Old Time is still a-flying;
And this same flower that smiles today
Tomorrow will be dying.