1. Exposition

What is the church called to keep?

Revelation 3:3 (ESV)

3 Remember, then, what you received and heard. Keep it, and repent. If you will not wake up, I will come like a thief, and you will not know at what hour I will come against you.

As a result of recalling their initial enthusiasm to the gospel, the church in Sardis is next instructed to keep (= guard, preserve) that passion.