The following is an excerpt from The MacArthur New Testament Commentary on Revelation 3.

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. He who has an ear, let him hear what the Spirit says to the churches. (3:5–6)

By way of encouragement, Christ described the rewards awaiting those who participated in the revival. True Christians, as already noted, will be clothed in white garments. In the ancient world, white garments were also worn for festive occasions such as weddings. True Christians will wear theirs at the marriage supper of the Lamb (19:7–9). White robes were also worn by those celebrating victory in battle; all true Christians are victorious through Christ over sin, death, and Satan. But, as noted earlier in the discussion of verse 4, primarily believers’ white garments represent purity and holiness. Christ promises to clothe Christians in the brilliance of eternal purity and holiness.

Christ further promises every true Christian that He will not erase his name from the book of life, but will confess his name before the Father and before His angels. Incredibly, although the text says just the opposite, some people assume that this verse teaches that a Christian’s name can be erased from the book of life. They thus foolishly turn a promise into a threat. Exodus 32:33, it is argued by some, supports the idea that God may remove someone’s name from the Book of Life. In that passage the Lord tells Moses that “whoever has sinned against Me, I will blot him out of My book.” There is no contradiction, however, between that passage and Christ’s promise in Revelation 3:5. The book referred to in Exodus 32:33 is not the Book of Life described here, in Philippians 4:3, and later in Revelation (13:8; 17:8; 20:12, 15; 21:27). Instead, it refers to the book of the living, the record of those who are alive (cf. Ps. 69:28). The threat, then, is not eternal damnation, but physical death.

In John’s day, rulers kept a register of the citizens of a city. If someone died, or committed a serious crime, their name was erased from that register. Christ, the King of heaven, promises never to erase a true Christian’s name from the roll of those whose names were “written from the foundation of the world in the book of life of the Lamb who has been slain” (13:8).

On the contrary, Christ will confess every believer’s name before God the Father and before His angels. He will affirm that they belong to Him. Here Christ reaffirmed the promise He made during His earthly ministry: “Everyone who confesses Me before men, I will also confess him before My Father who is in heaven” (Matt. 10:32). The comforting truth that true Christians’ salvation is eternally secure is the unmistakable teaching of Scripture. Nowhere is that truth more strongly stated than in Romans 8:28–39:  And we know that God causes all things to work together for good to those who love God, to those who are called according to His purpose. For those whom He foreknew, He also predestined to become conformed to the image of His Son, so that He would be the firstborn among many brethren; and these whom He predestined, He also called; and these whom He called, He also justified; and these whom He justified, He also glorified. What then shall we say to these things? If God is for us, who is against us? He who did not spare His own Son, but delivered Him over for us all, how will He not also with Him freely give us all things? Who will bring a charge against God’s elect? God is the one who justifies; who is the one who condemns? Christ Jesus is He who died, yes, rather who was raised, who is at the right hand of God, who also intercedes for us. Who will separate us from the love of Christ? Will tribulation, or distress, or persecution, or famine, or nakedness, or peril, or sword? Just as it is written, “For Your sake we are being put to death all day long; we were considered as sheep to be slaughtered.” But in all these things we overwhelmingly conquer through Him who loved us. For I am convinced that neither death, nor life, nor angels, nor principalities, nor things present, nor things to come, nor powers, nor height, nor depth, nor any other created thing, will be able to separate us from the love of God, which is in Christ Jesus our Lord.The letter to Sardis ends, like the other six, with an exhortation to heed the counsel, commands, and promises it contains: He who has an ear, let him hear what the Spirit says to the churches. The spiritually dead zombies playing church needed to heed Christ’s warning of impending judgment. The indifferent believers needed to wake up before it was too late to save their church. And the faithful few could take comfort in the knowledge that their salvation was eternally secure.

What happened to Sardis? Did they heed the warning? Did revival come? That such a prominent man as Melito served as bishop of Sardis several decades after John wrote argues that at least some revival took place in Sardis. Until Christ returns, it is not too late for other dead churches to find the path to spiritual renewal.