Revelation 1 God's Revelation about the final time. The time is near. The end of the world.

From whom and to whom was the revelation given?
It is a revelation of Jesus Christ, the Son of God. It is a revelation to the apostle John so that mankind knows what will happen in the end of times, the Great Tribulation. Chapters 2 and 3 are addressed to the church, to which Jesus gives serious warnings. From chapter 4 we no longer see the church on earth. The church of Christ is taken up into Heaven, chapter 4. From chapters 5 to 20, follows what will happen on earth. These are serious warnings to humans. It is man's FREE CHOICE to accept Jesus Christ as Savior and Lord and take these warnings to heart. Or to choose (in disbelief and) in rejection to pass through the Great Tribulation.
Who was the apostle John?
John was the fourth apostle called by Jesus, brother of James, Matthew 4:21. Matthew 17:1-13 Jesus took Peter, James, and John to a high mountain, where Jesus was transfigured and Moses and Elijah (the two witnesses Revelation 11:1-14). On the mountain, Jesus showed something of His divine nature.
John wrote the fourth gospel and 3 letters. He is told what is happen in the future, the soon-to-come days of the Great Tribulation.
Why should the Christian publish and study the book of Revelation?
Revelation 1:3 It is the command of Jesus Christ to man, and especially to the Christian, to make known and explain the book of Revelation. Whoever does that is blessed by Him. For the time is near. With the Lord one day is as a thousand years, and a thousand years as one day (2 Peter 3:8). This revelation was given to John nearly 2,000 years ago, but for God just two days ago. The signs that Jesus said are clearly visible NOW. The corona virus captivates the WHOLE WORLD. The other signs are clearly visible, everything described in Revelation is what governments are doing. One world power, no more individual presidents and kings. One currency and no more paper money. Testing a chip in the hand (Sweden, Germany and the United Kingdom, United Arab Emirates) with which one pays. Everything in preparation for the AntiChrist. God keeps NOTHING HIDDEN it is fully told in Revelation to the apostle John, about 2000 years ago
The Salutation of Revelation
The assignment in Rev. 1:11 is to send it to the seven churches in Asia. John sends the letter to ALL seven congregations in Asia. And is NOW available to ALL believing Christians. No Christian has an excuse to say, I DID NOT KNOW. The Bible is freely available on the Internet. It is the DUTY of every Christian to study the Bible and now especially Revelation. The Christians who are left behind Matthew 24:40-41 will have no excuse in the Great Tribulation for I DID NOT KNOW, and they can then take note of what will happen in those seven years. Then they can already make their decision and know the consequences of their choice.
Jesus Christ is the firstborn from the dead. Jesus was the first to rise from the dead and afterwards no longer died but ascended to Heaven, where He sits at the right hand of God the Father. He has defeated satan at the Cross of Calvary. He has defeated death. He has thereby taken over the power of satan and is the ruler of kings on earth. Today is satan's tremendous efforts to take over world power. The last attempt is in the soon-coming Great Tribulation. Many will run after satan. Worship satan because people DO NOT wish God above them. But their end is described in Revelation 20.
Verse 7 is a confirmation of Matthew 24:29-30 Immediately after the tribulation of those days (=at the end of the Great Tribution) .... then all the tribes of the earth will mourn, and they will see the Son of man coming on the clouds of heaven with power and great glory.
Zechariah 12:10 when they look on him whom they have pierced. They are the Jews and Israelites, but also the Gentiles who were present at the crucifixion of Jesus. So it includes all nations on earth at the end of the Great Tribulation. Remember that Jesus is Omnipresent, He is God, not bound to a place (in the fourth dimension there is no time, so no distance), so He can be seen by everyone on earth.
Zechariah 14:4 (Jesus) On that day his feet shall stand on the Mount of Olives which lies before Jerusalem.
Why should we take the book of Revelation seriously?
John turns to see who speaks these words and sees Jesus. Verse 14 corresponds to the description in Daniel 7:9 His raiment was white as snow, and the hair of his head like pure wool; his throne was fiery flames, its wheels were burning fire. Here we no longer see Jesus as a prince of peace, as a Savior and Love, but as a JUDGE (God is a devouring fire Deut. 4:24, Heb. 12:28), Who comes to judge the world and people (also from the Great Tribulation), satan and demons.