Revelation 3:4

‘But you have a few names (people) in Sardis who did not defile (spoil) their clothing, and they will walk with me in white, for they are worthy.'

Sardis was a centre for the manufacture and dyeing of woollen garments. They knew what it meant for clothing to be ruined in the process of manufacture and dyeing, and that is what the church themselves have done with their spiritual garments. They have totally ruined them. They are useless. No longer are they concerned to be clothed in the righteousness of Christ. No longer do they seek to live as He directed. Their whole lives are spoiled spiritually.

Yet even here there are a few who still enjoy unspoiled clothing, and in the future they will enjoy the finest. Walking in white is always the symbol of purity and acceptability to God (see Revelation 6:11; Revelation 7:14; Revelation 19:8), and is distinctive of heavenly beings.

So there is no live fellowship in Sardis, but, here and there, there are scattered Christians who are still living clean, pure Christ-like lives, and are still worshipping Him and experiencing the Spirit's presence. God does not condemn the few because of the many, for there is nothing they can do about the situation. Sin can be cast out but not coldness. They need not fear. They will not lose out because of their solitary state. They will receive their due. Perhaps the mention of ‘names' (which here simply means ‘specific people') has in mind that they are remembered before God, because their names are in the Book of Life. Though they seem to be forgotten He knows them by name, and their names are recorded (v. 5).