Jesus has just said to the church in Sardis that He knows their works, that they have a reputation of being alive, but they're dead. Verse 2 gives us a glimmer of hope. He says,
Wake up, and strengthen what remains and is about to die, for I have not found your works complete in the sight of my God. (Revelation 3:2)
As is the case with all of these churches, Christ shows mercy and longsuffering. Already, they deserve to have their lampstand removed, yet the Lord gives them another chance. He tells them to "Wake up." If this season of their church's life could be compared to a slumber, it was time for them to wake up.
What that looks like is strengthening "what remains and is about to die." The church wasn't completely dead. It had remnants of the basics of a church. What are these basics? Here's a sample list, though it may not be comprehensive:
The Bible is taught faithfully from week to week
The church members love God and each other sincerely
The church practices discipline and accountability
The church engages in evangelism and missions
There was perhaps some of this in the church in Sardis, though very little. What little flame they had was about to die off. Christ calls them to wake up and strengthen what they have left. And He gives this reason: "for I have not found your works complete in the sight of my God." In other words, what little they had left was not enough. This is not to say that the Christians there weren't saved. This is to say that they were on the brink of losing their right to be a witness of Christ in Sardis. If they didn't repent, Christ was going to remove the local church there.
Sadly, there is little to no sign of Christian presence or witness in modern-day Sart. It seems as if they didn't repent, and Christ did take away their lampstand.
But the church in Sardis still serves the church today. It serves as a warning. We need to ensure that we consistently go back to the basics and remain alive as a visible church. We shouldn't look to worldly standards of being a vibrant organization. We need to look at Christ's standards, lest He says that our church has the reputation of being alive but is actually dead (v. 1). May He who sustains us and saves us help us!