Revelation 3:1-3

“To the angel of the church in Sardis write: He who has the seven spirits of God and the seven stars, says this: ‘I know your deeds, that you have a name that you are alive, and yet you are dead.

Be constantly alert, and strengthen the things that remain, which were about to die; for I have not found your deeds completed in the sight of My God.

So remember what you have received and heard; and keep it, and repent. Then if you are not alert, I will come like a thief, and you will not know at what hour I will come to you.