Revelation 3:2-4

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. Thou hast a few names even in Sardis which have not defiled their garments; and they shall walk with me in white: for they are worthy.