Patmos is a small, rocky island in the Aegean Sea, off the coast of modern Turkey, used by the Romans as a place of exile. There the apostle John was banished for the word of God, and for the testimony of Jesus Christ — an old man, cut off from his churches, apparently silenced.
But it was on lonely Patmos that John received the Revelation of Jesus Christ — the visions of the throne, the Lamb, the fall of evil, and the new creation. The place of exile became the place of the greatest unveiling of Christ's glory and victory. Patmos stands as a reminder that God can meet his people, and speak his clearest word, in the most isolated of places.
Patmos in Scripture
I John, who also am your brother, and companion in tribulation, and in the kingdom and patience of Jesus Christ, was in the isle that is called Patmos, for the word of God, and for the testimony of Jesus Christ.