Given that thunder is the voice of God in judgment, it seems to further the notion that these mysteriously sealed instructions may be judgments.
John MacArthur wrote of the Seven Thunders in his book Because the Time is Near:
The seven peals of thunder did not merely make a loud noise, but communicated information that John was about to write. In obedience to God's commands, John had already written much of what he saw in his visions. Later in Revelation, John would once again be commanded to write what he saw in his visions. (14:13; 19:9; 21:5).Let's focus in on the "too terrifying" part of the reasoning here. In all the apocalyptic movies I've ever seen specifically related to the Tribulation, they are all uniformly sanitized. In other words, the horrific reality of the Tribulation as depicted in the Bible's Book of Revelation has been visually watered down to be as non-reflective of the reality of a cellophane wrapped hamburger meat at Publix is compared to the blood, filth and messiness of a low-rent butchery. And even that is not reflective of the reality of what is coming.
But before John could record the message of the seven peals of thunder, he heard a voice from heaven saying, "Seal up the things which the seven peals of thunder have spoken and do not write them."Whether the voice was that of the Father, or Jesus Christ, or an angel is not revealed. The command, however, clearly originated with God. The reason John was forbidden to record the message is not revealed. It may be that the judgments were simply too terrifying to be recorded. Any speculation as to the content of their message is pointless. If God wanted it to be known, He would not have forbidden John to write it. They are the only words in the book of Revelation that are sealed.
The non-Christian apocalyptic movies movies I've seen, Threads, The War Game, and It's A Disaster, were harrowing and soul-slaying. Their real depiction of nuclear or nerve gas apocalypse stayed with me for a long time. The War Game was commissioned by the BBC to specificaly illutrate the horrors of nuclear war and the Board found the movie too realistic to be released for thirty years, and even that film doesn't go the distance of what the reality of the Tribulation will be like in terms of nuclear anguish and death. People just do not understand what it really means when Jesus promised it to be a time of distress exceeding even the time of the Flood. (Matthew 24:21). And remember, that was a time when everybody on earth died. (Except 8 people)
So here is Oliver B. Greene in his Verse-By-Verse Study of Revelation, on the Seven Thunders' terror:
Thunder is the voice of the Lord in judgment (I Samuel 7:10, Psalm 18:13). The seven thunders “uttered their voices.” (John assumes that the readers already have Some knowledge of these seven thunders.) In Revelation 4:2, 3 John saw a throne encircled by a rainbow, and here in chapter ten we see the same rainbow. In Revelation 4 John saw upon the throne One who was to look upon as a jasper and a sardine stone, and “out of the throne proceeded lightnings and thunderings and voices.” In chapter 10, we have the same thunder, sounding out a message of God’s fury and judgment.Imagine a message that exceeds the terror and blood of all that had already previously been spoken. Or if that was not the case, imagine a message that was so tremendously powerful it needed to be sealed from our tender brains until the moment they would be spoken during the Tribulation.
The seven thunders are the judgment thunders from the throne of God. When the Lion of the Tribe of Judah roars, as on the eve of bounding forth upon His prey, the seven thunders utter their roaring voices as in full sympathy and agreement with what is about to proceed in righteous vengeance and holy fury from the throne of eternal majesty. Personality is attributed to these “seven thunders.” Everything is in sympathy with the Lamb of God. These mighty thunders utter messages that are intelligible . . . they speak words. John heard what they said - and when the time comes in reality, the seven thunders will speak literal words that earth’s dwellers will fully understand. It will be a message in tones of thunder. We use a public address system to amplify voices when we want to be heard - but God needs no amplification. He can speak like mighty thunder - and He WILL when the time comes!
At the beginning of these marvelous visions, John was commanded to write in a book what he saw and heard - past, present and future. But when the thunders spoke, John was given another command. He was about to write - but a voice from Heaven said: “Seal up those things which the seven thunders uttered, and write them not!” The seven thunders must have given a terrible message. Already set before us are blood, tears, famine, heartache and heartbreak; killing, misery, hail, fire, burning mountains, demon monstrosities, men begging to die and unable to do so. Surely what John was forbidden to write must have been beyond human imagination and understanding! There is no need to speculate on what the thunders said. Your guess is as good as mine; but you may rest assured that the message had to do with God’s last gigantic, unheard of, indescribable judgment, when God “lowers the boom” in utter destruction.
Will YOU be on earth when the seven thunders speak? You are the only one who can answer that question. If you are born again you will NOT be here - but if you are not born again, you may be here. Read John 1:11-12, 3:16-18, 3:36, 5:24; Romans 10:9-10, 10:13, 10:17; Ephesians 2:8-9; I John 1:9. Read these verses, hear what they say; receive them - and you will not be here when the seven thunders utter their message of destruction. You will be with Jesus.
Prophecy is supposed to motivate us to witness, and yet the reality of the judgments of souls in rebellion to God is omitted from the message of the Good News. How terrible that it's omitted so often these days, when the days are coming that many will be living it!
May this essay motivate you to read Revelation, to pray for wisdom and understanding of the coming days, to receive the promised blessing for having read it,, and for its words to be a catalyst in your heart for the lost who are under that very "boom" Greene mentioned, soon to be lowered...