ARIEL: While you here do snoring lie,
Open-eyed conspiracy
His time doth take.
If of life you keep a care,
Shake off slumber and beware.
Awake, awake!

William Shakespeare (1564-1616) English dramatist and poet

Tempest, Act 2, sc. 1, l. 344ff (2.1.344-349) (1611)
    (Source)

Warning the sleeping Gonzalo of Antonio and Sebastian's plot to kill Alonso.