Because of the word of God and the testimony of Jesus.

Revelation 1:9, I, John, your brother and fellow partaker in the tribulation and kingdom and perseverance which are in Jesus, was on the island called Patmos, because of the word of God and the testimony of Jesus.

One of the surest testimonies we have is the lives of the early believers; John was the only one not put to death for his faith, and apparently not for lack of trying. We like the idea of His kingdom, and without His perseverance we would be lost. John also accepted tribulation as part of the package in his exile from those whom he loved. We have to look to Him as John did when trouble comes.

We look only to You Lord; all our hope is in You!