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.
We may understand this to refer to justification. “They shall walk in white;” that is, they shall enjoy a constant sense of their own justification by faith; they shall understand that the righteousness of Christ is imputed to them, that they have all been washed and made whiter than the newly-fallen snow.\n The promise also refers to walking in white before the throne of God. Those who have not defiled their garments here shall most certainly walk in white up yonder, where the white-robed hosts sing perpetual hallelujahs to the Most High. They shall possess joys inconceivable, happiness beyond a dream, bliss which imagination knoweth not, blessedness which even the stretch of desire hath not reached. The “undefiled in the way” shall have all this–not of merit, nor of works, but of grace. They shall walk with Christ in white, for he has made them “worthy.” In his sweet company they shall drink of the living fountains of waters.
Charles H. Spurgeon, Morning and Evening