Albert Barnes Commentary Revelation 8:4

"And the smoke of the incense, with the prayers of the saints, went up before God out of the angel`s hand." — Revelation 8:4 (ASV)

And the smoke of the incense, etc. The smoke caused by the burning incense. John, as he saw this, naturally interpreted it as the prayers of the saints. The meaning of the whole symbol, explained in this way, is that at the time referred to, the anxiety of the church regarding the events which were about to occur would naturally lead to much prayer. It is not necessary to attempt to verify this with any specific historical facts, because no one can doubt that in a time of such impending calamities, the church would be earnestly engaged in devotion. This has always been the case in times of danger; and it may always be assumed to be true that when danger threatens, whether it is to the church at large or to an individual Christian, there will be a resort to the throne of grace.