The only biblical mention of the church in the town of Sardis is as the recipient of one of the letters that John sent to seven churches in the province of Asia (for map see ASIA). Nothing is known of the church apart from what is found in this letter.
So much had the church in Sardis followed the ways of the society around it, that it was Christian in name only. Spiritually it was dead. Unless the Christians woke up and changed their ways, God would act against them in swift judgment. There were some, however, who proved the genuineness of their faith by refusing to alter their behaviour to suit the majority. Such people were assured of God’s reward (Revelation 3:1-6).