Revelation 3:2-3 NIV

2 Wake up! Strengthen what remains and is about to die, for I have found your deeds unfinished in the sight of my God.
3 Remember, therefore, what you have received and heard; hold it fast, and repent. But if you do not wake up, I will come like a thief, and you will not know at what time I will come to you.

References for Revelation 3:3