Revelation 3:4: Thou hast a few names even in Sardis which have not defiled their garments; and they shall walk with me in white: for they are worthy.

Apostasy had already gripped the church in Sardis by 96 AD,¹ leaving only a few names (persons)² in this wicked city³ which have not defiled their garments.⁴ This play on words⁵ describes a people inwardly defiled⁶ and outwardly preoccupied by their name and stature in a town famous for its garment industry.⁷ Within the church, only a few saints remained⁸ whose outward expression of faith and holiness mirrored their inward purity.⁹

Garments represent covenant making,¹⁰ and undefiled garments symbolize¹¹ covenant keeping.¹² Today, endowed members of The Church of Jesus Christ of Latter-day Saints¹³ wear sacred garments as a token or sign of covenants they have made with God in the temple.¹⁴ They wear the temple garment as an outward expression of their inward submission to God's will¹⁵ and their inner character.¹⁶ Under the Mosaic Law, only those with undefiled garments were ceremonially clean for purposes of temple worship.¹⁷

Saints that have clean and undefiled garments shall be exalted,¹⁸ for they are worthy to walk with [Christ] in white robes of glory.¹⁹ Similarly, a bride clothed in a white dress symbolizes exaltation in Revelation 19:8.²⁰ White clothing represents righteousness and purity.²¹ In the practices of the Jewish Sanhedrin,²² white clothing was given to a candidate deemed worthy to receive the high priesthood.²³

Revelation 3:5: He that overcometh, the same shall be clothed in white raiment; and I will not blot out his name out of the book of life, but I will confess his name before my Father, and before his angels.

Saints in all ages inherit eternal life as they overcome tribulation and endure to the end.²⁴ They shall be clothed in white raiment²⁵ as a symbol of their glory and exaltation.²⁶ The image of white clothing was especially meaningful to the clothing manufacturers of Sardis.²⁷ Also, because the name and reputation of the church was important to them,²⁸ Christ states: I will not blot out [the overcomer's] name out of the book of life.²⁹

Moses had a book of life to record the names of Israelites according to their tribe.³⁰ The Sardian saints clearly understood the metaphorical meaning of this historical reference.³¹ The book of life refers to a record³² actually kept in heaven³³ with the names of those that qualify for eternal life.³⁴

People can have their names written in the book of life either in the premortal existence³⁵ or in this mortal existence.³⁶ When this occurred for valiant spirits in the premortal existence,³⁷ it meant they were foreordained to exaltation.³⁸ This is called the election of grace and it pertains to people literally born into the lineage of the house of Israel.³⁹ People can also have their names written in the book of life in mortality as they receive gospel ordinances⁴⁰ and become adopted into the lineage of Abraham.⁴¹ In either case, people must overcome trials and temptations through obedience to the laws of the gospel in this life, or their names will be blotted out from the book of life.⁴²

Saints that have their names in the book of life belong to Christ, and they will be exalted.⁴³ Christ will be their advocate with the Father in the day of their judgment.⁴⁴ He will confess (i.e., plead)⁴⁵ their righteous works⁴⁶ before the Father and before his angels.⁴⁷ In that day, Christ will confess the names of those written in the book of life,⁴⁸ but not those whose names are blotted out. For such people, their name and worldly reputation is more important to them than to confess the name of Christ as his disciples.⁴⁹

Revelation 3:6: He that hath an ear, let him hear what the Spirit saith unto the churches.

Saints that are wicked and disobedient in this life will have their names blotted out from the book of life⁵⁰ by the time of their physical death,⁵¹ unless their calling and election is made sure.⁵² If their names are missing from the book of life in the day of their judgment they will not inherit eternal life.⁵³ Christ emphatically warns people of this possibility in all ages, saying: He that hath an ear, let him hear what the Spirit saith unto the churches.⁵⁴