Revelation 3:5

white--not a dull white, but glittering, dazzling white [GROTIUS]. Compare Mat 13:43. The body transfigured into the likeness of Christ's body, and emitting beams of light reflected from Him, is probably the "white raiment" promised here. the same--Greek, "THIS man"; he and he alone. So one oldest manuscript reads. But two oldest manuscripts, and most of the ancient versions, "shall THUS be clothed," &c. raiment--Greek, "garments." "He that overcometh" shall receive the same reward as they who "have not defiled their garments" (Rev 3:4); therefore the two are identical. I will not--Greek, "I will not by any means." blot out . . . name out of . . . book of life--of the heavenly city. A register was kept in ancient cities of their citizens: the names of the dead were of course erased. So those who have a name that they live and are dead (Rev 3:1), are blotted out of God's roll of the heavenly citizens and heirs of eternal life; not that in God's electing decree they ever were in His book of life. But, according to human conceptions, those who had a high name for piety would be supposed to be in it, and were, in respect to privileges, actually among those in the way of salvation; but these privileges, and the fact that they once might have been saved, shall be of no avail to them.

— Jamieson-Fausset-Brown Commentary (public domain)