We use the term with reference to what we do at the end of our night’s sleep. That, however, is not the meaning of the word that appears here. It is repeatedly used in Scripture to denote being alert (as opposed to sleeping), as what a watchman must do in guarding against danger. Specifically, the term is used in relation to being attentive to Christ’s imminent return (Matthew 24:42; Mark 13:35; 1 Thessalonians 5:6; 1 Peter 5:8). The apostles who first preached the gospel had seen the resurrected Christ with their own eyes, had seen him ascend into heaven, and had heard him say that he would return soon. The expectation of his impending return was the dynamic that gave the apostles the drive to preach the gospel with urgency. With the word translated as “wake up” the Lord in this letter is urging the Christians of Sardis to be alert and ready for his return.
2 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.