John saw an angel coming down from heaven. He seized, bound, and imprisoned the dragon for 1,000 years.

Revelation 20:1-3

20 I saw an angel coming down from heaven. He had the key to the deep dark pit, and he was carrying a large chain in his hand. 2 He seized the dragon. That dragon is the ancient serpent, the devil, that is, Satan. The angel bound him with the chain. That chain could not be loosed {No one could loose that chain} for 1,000 years. 3 The angel threw him into the deep dark pit. He shut the door of the pit, locked it, and sealed it to prevent anyone from opening it. He did that in order that Satan might no longer deceive the people of the nations [MTY], until those 1,000 years are ended. After that time, Satan must be released {God/God’s angel must release Satan} for a short time in order that he can do what God has planned.