KEATING: “Seize the day.” “Gather ye rosebuds while ye may.” Why does the writer use these lines?

CHARLIE: Because he’s in a hurry.

KEATING: No. Ding! Thanks for playing anyway. Because we are food for worms, lads. Because, believe it or not, each and every one of us in this room is one day going to stop breathing, turn cold, and die.

Tom Schulman (b. 1951) American screenwriter, director

Dead Poets Society (1989)
    (Source)

See Herrick and Horace.