Expositor's Bible Commentary Commentary Revelation 3:3

"Remember therefore how thou hast received and didst hear; and keep [it], and repent. If therefore thou shalt not watch, I will come as a thief, and thou shalt not know what hour I will come upon thee." — Revelation 3:3 (ASV)

Like those in Ephesus, the Sardians must remember what they “have received and heard.” What they “received” was the apostolic tradition of the gospel; what they “heard” probably were the teachings of the apostles and prophets who brought the gospel to them. Unlike the church at Philadelphia (v.8), the Sardians were not holding to the word of Christ. For them repentance was the only way out of certain and final death. So they were to repent by restoring the gospel and the apostolic doctrine to its authority over their lives. This would mean they would once more start to “obey” (lit., “keep”; GK 5498) the truth of Christ’s word. Today’s church needs to hear this challenge to take the word of Christ seriously. If the church at Sardis does not repent, Christ will come to them in judgment “as a thief”—i.e., by surprise. This phrase should probably not be taken as referring to the Second Coming but to Christ’s opposing them in judgment (cf. his threat to the church in Ephesus in 2:5).