"And to the angel of the church in Sardis write,'These things says He who has the seven Spirits of God and the seven stars: "I know your works, that you have a name that you are alive, but you are dead.
Be watchful, and strengthen the things which remain, that are ready to die, for I have not found your works perfect before God.
References for Revelation 3:2
Remember therefore how you have received and heard; hold fast and repent. Therefore if you will not watch, I will come upon you as a thief, and you will not know what hour I will come upon you.
You have a few names even in Sardis who have not defiled their garments; and they shall walk with Me in white, for they are worthy.
References for Revelation 3:4
He who overcomes shall be clothed in white garments, and I will not blot out his name from the Book of Life; but I will confess his name before My Father and before His angels.
He who has an ear, let him hear what the Spirit says to the churches." '