Be watchful over your life. Never let your lamps go out or your loins be ungirded, but keep yourselves always in readiness. For you can never be sure the hour when the Lord may be coming.
Didache 16.1 (ca. 90-100 CE)
Commentary: This old text is an early Christian handbook that contains traditions about as old as any we can recover from surviving Christian documents. The first Christians were very millenarian.