Revelation 3:1-3

And to the angel of the church in Sardis write: These things saith he that hath the seven Spirits of God, and the seven stars: I know thy works, that thou hast a name that thou livest, and thou art dead. Be thou watchful, and establish the things that remain, which were ready to die: for I have found no works of thine perfected before my God. Remember therefore how thou hast received and didst hear; and keep it, and repent. If therefore thou shalt not watch, I will come as a thief, and thou shalt not know what hour I will come upon thee.