Revelation 3:2-3

"Be watchful, and strengthen the things which remain, that are ready to die: for I have not found thy works perfect before God. 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" - Revelation 3:2-3 KJV