1 Thessalonians 5:6-8

This is why we must not fall asleep, as the rest do, but keep wide awake and clearheaded. For those who are asleep sleep the night away, and drunkards get drunk at night. But since we belong to the day, we must stay alert and clearheaded by placing the breastplate of faith and love over our hearts, and a helmet of the hope of salvation over our thoughts.