In Revelation 10, an angel comes to John, this time with a smaller scroll – or a smaller book, in some translations. The angel tells John that the seventh angel is about to blow the trumpet, and as he does, the mystery of God will be accomplished.
But in the days when the seventh angel is about to sound his trumpet, the mystery of God will be accomplished, just as he announced to his servants the prophets.”
Revelation 10:7
There is a lot of speculation about what this mystery is and what it is that will be accomplished. However, I don’t think that there needs to be much confusion. Jesus had come to reestablish his Kingdom, his rule and reign, on the earth. It had been his, but God’s people had rejected him, choosing instead to have a human king just like all of the nations that surrounded them.
But as Jesus came, he proclaimed to the people that the Kingdom of God had come near to them and that they needed to repent and believe. They needed to repent from their sins and believe in Jesus as both Savior as well as Lord, or King, over their lives. And so this is the mystery, that God Himself comes in the form of a man, in the form of Jesus Christ, to seek both Jews and Gentiles that he will purchase for God through his own blood, his own death on the cross. God Himself becomes the sacrifice that will bring forgiveness.
This is the same outcome that had been announced as the reason that the Lamb was worthy to break the seals on the scroll:
“You are worthy to take the scroll
and to open its seals,
because you were slain,
and with your blood you purchased for God
persons from every tribe and language and people and nation.You have made them to be a kingdom and priests to serve our God,
Revelation 5:9-10
and they will reign on the earth.”
And this is the same outcome that is proclaimed just as soon as the seventh angel sounded his trumpet:
“The kingdom of the world has become
Revelation 11:15
the kingdom of our Lord and of his Messiah,
and he will reign for ever and ever.”
The mystery, I believe, is exactly this, that God has returned to the earth in the form of Christ to rule and reign on the earth. He has done it once before, and he is returning to do it again.