“And to the angel of the church in Sardis write: He who has the seven Spirits of God, and the seven stars [i.e. messengers of the seven churches – Rev. 1:20], says this: ‘I know your deeds [omniscience], that you have a name that you are alive [a false reputation], but you are dead [νεκρός nekros – most likely a reference to being out of fellowship with God]. 2 ‘Wake up [γίνου γρηγορῶν – or be alert, be watchful] and strengthen [στηρίζω sterizo – strengthen, establish – aor/act/imp] the things that remain, which were about to die; for I have not found your deeds completed [i.e. divinely assigned tasks; cf. Eph. 2:10] in the sight of My God. 3 ‘Remember therefore what you have received and heard [i.e. recall biblical teaching]; and keep it [i.e. guard it, watch over it], and repent [turn back]. If therefore you will not wake up [3rd class condition – possible future], I will come like a thief [unannounced and unexpected], and you will not know at what hour I will come upon you [for discipline]. 4 ‘But you have a few people in Sardis who have not soiled their garments [i.e. a faithful remnant]; and they will walk with Me in white; for they are worthy [ἄξιος axios – worthy, deserving – because they executed their spiritual duties]. 5 ‘He who overcomes [νικάω nikao – to conquer, prevail – i.e. is saved and obedient] shall thus be clothed in white garments [a reward for obedient saints; see Rev. 19:8]; and I will not [οὐ μὴ ou me – emphatic negative = not never] erase his name from the book of life [the ledger of the saved], and I will confess his name before My Father, and before His angels. 6 ‘He who has an ear [the spiritually sensitive believer], let him hear what the Spirit says to the churches.’” (Rev. 3:1-6)

Summary:

     Jesus states the church has a public name that they are “alive”, but in fact most were abiding in death. The church was spiritually alive, so this likely refers to carnal death (Luke 15:24, 32; James 1:14-15), which meant they were out of fellowship with God and operating according to their sinful natures (Rom. 6:6; 13:14; Col. 3:9). Similarly, there are many churches today that reside in beautiful structures and have many programs, yet do not teach God’s word and show little signs of spiritual life. These believers were alive, but asleep. The call from Jesus was to “wake up and strengthen the things that remain, which were about to die” (Rev. 3:2a). He declares, “I have not found your deeds completed in the sight of My God” (Rev. 3:2b). This alludes to the idea that all believers have specific works that God creates and calls us to walk in, but we must accept those opportunities (Eph. 2:10). He then calls them to “remember” what they had heard, which refers to biblical teaching that guides the Christian life; and, they were to “keep it” close and safe (i.e. guard it), and “repent” by turning back to a walk of obedience (Rev. 3:3a). He warns them with a threat of judgment, saying, “If therefore you will not wake up, I will come like a thief, and you will not know at what hour I will come upon you” (Rev. 3:3b). God will send discipline upon the believer who turns away from Him (Heb. 12:5-11). Jesus then addresses the faithful remnant within the church, those “who have not soiled their garments” by worldly living (Rev. 3:4a), and declares, “they will walk with Me in white, for they are worthy” (Rev 3:4b). This implies reward for obedience. Jesus states, “He who overcomes will thus be clothed in white garments; and I will not erase his name from the book of life, and I will confess his name before My Father and before His angels” (Rev. 3:5). “While this passage may imply that a name could be erased from the book of life, actually it onl