Revelation 3:3

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.

So remember and take to heart the lessons you have received and heard. Keep and obey them, and repent [change your sinful way of thinking, and demonstrate your repentance with new behavior that proves a conscious decision to turn away from sin]. So then, if you do not wake up, I will come [omit] like a thief, and you will not know at what hour I will come to you.