The Greek verb agrypneō means to be sleepless, to keep watch, or to stay alert. It occurs 4 times in the New Testament and carries the sense of vigilant, purposeful wakefulness — not mere biological alertness but the spiritual discipline of remaining watchful and sober-minded in the face of spiritual danger.
Agrypneō is the pastor's word and the soldier's discipline. Paul uses it for apostolic ministry: 'I have been constantly on the move... I have labored and toiled and have often gone without sleep (agrypniais)' (2 Corinthians 11:27). He charges the Ephesian elders to 'keep watch over yourselves and all the flock' (Acts 20:31), using the related grēgoreō. In Hebrews 13:17, leaders 'keep watch over your souls as those who will give an account.' Jesus's call to 'watch and pray' underlies this entire vocabulary of vigilance. The opposite of agrypneō is the spiritual drowsiness that makes believers vulnerable to temptation and false teaching.