John 3:18
Rev. 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.
Here God/Jesus is talking not to the unsaved, but to the “Churches.” When I walked away from the Catholic Church and embraced evangelical Christianity they preached what many here proclaim...once saved, once forgiven, you can do no wrong, Book of Life, you have been given a white robe...etc.
But I would suggest to many to read Revelation 2 and 3 very carefully. For God is not talking to the unsaved, he is talking to the ‘saved’ and those who ‘believe’ they are saved. And at each verse he reminds them to repent again AND have ‘good works.’
God clearly tells us that our ‘saved names’ can be blotted out of the Book of Life...because we defiled our robes, because we failed to have good works AFTER “believing” in His grace. Repentance is not a one time thing, for no man’s works are perfect.
God tells us as Christians we must overcome the coming trials and tribulations. Being ‘saved’ isn’t going to be enough to get the white robe, sit at the throne, or walk with Jesus in Heaven.
The sacrament of repentance, is not a one time thing, for every Christian can defile his robe...for we are but humble humans.