I John, who also am your brother, and companion in tribulation, and in the kingdom and patience of Jesus Christ…
1. To be in the Spirit is to possess the Spirit.
2. The second thing referred to is the time of the vision: "The Lord's Day." It is His Day because it is the day of His Divine appointment. This is the day which the Lord hath made; we will be glad and rejoice in it. And it is His day because He is the subject of it. His personal glory; His victory and triumph over death and the grave; His holding the keys of hell and of death; from the subjects of holy meditation on this blessed day.
Parallel VersesKJV: 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.