Revelation 3:1-3 (KJV)
1 And unto 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 art dead.
2 Be watchful, and strengthen the things which remain, that are ready to die: for I have not found thy works perfect before God.
3 Remember therefore how thou hast received and heard, and hold fast, and repent. If therefore thou shalt not watch, I will come on thee as a thief, and thou shalt not know what hour I will come upon thee.