Revelation 7:15 - Matthew Poole's English Annotations on the Holy Bible

Therefore are they before the throne of God; not that they by their sufferings have merited heaven, but because it pleaseth God of his free grace so to reward them; therefore it was said, not only that they were such as came out of tribulation, but that they had washed their garments in the blood of the Lamb, whose blood had paid the price of their salvation. And serve him day and night in his temple: by the temple, some understand the church in this life, but it is foreign to the true sense of the text; for John saw only their souls before the throne, their bodies were in their graves. By the temple is meant heaven, where God dwelleth, and is worshipped more gloriously and constantly than he was in the Jewish temple, or in any part of the militant church. And he that sitteth on the throne shall dwell among them; as God by his gracious presence dwelt in the Jewish temple, so God by his glorious presence shall dwell amongst his glorified saints.