Revelation 10: 1 – 4: And I saw another mighty angel come down from heaven, clothed with a cloud: and a rainbow was upon his head, and his face was as it were the sun, and his feet as pillars of fire: And he had in his hand a little book open: and he set his right foot upon the sea, and his left foot on the earth, And cried with a loud voice, as when a lion roareth: and when he had cried, seven thunders uttered their voices. And when the seven thunders had uttered their voices, I was about to write: and I heard a voice from heaven saying unto me, Seal up those things which the seven thunders uttered, and write them not.
A thunder is symbolic of a voice, therefore the seven thunders symbolize seven utterings of God. This can be plainly seen in John 12: 28 – 29: Father, glorify thy name. Then came there a voice from heaven, saying, I have both glorified it, and will glorify it again. The people therefore, that stood by, and heard it, said that it thundered: others said, An angel spake to him.
Revelation 10 shows that what God had spoken was sealed up, thus the seven thunders or utterings of God were sealed with seven seals. But John also recorded that the closed and sealed Book in Revelation 5 had become open in Revelation 10, showing that the contents of the Book were now plain for all to see. The seven seals are therefore the covering of the Book, but the seven thunders are the contents of the Book.
The Book is the Bible, It is the Title Deed, and It is the Lamb’s Book of Life; It is the eternal thinking of God in print form. The Book being open in Revelation 10 means that the seven seals have been ripped off the Book and the contents of the Book are now revealed. The contents of the Book are the seven thunders, and the seven thunders are the secrets of God revealed to the Bride by the Holy Ghost. To put it simply, when God reveals His Word to a person, when He reveals the mystery of Himself to a person, that is the seven thunders uttering their voices.