Revelation

The Revelation of Jesus Christ, which God gave unto him, to shew unto his servants things which must shortly come to pass; and he sent and signified it by his angel unto his servant John

Very simply, John was told by an angel[most likely Gabirel] who was sent by God, revelations. These revelations are what this book is about.

Who bare record of the word of God, and of the testimony of Jesus Christ, and of all things that he saw.

John recorded what Jesus told him in his revelation.

Blessed is he that readeth, and they that hear the words of this prophecy, and keep those things which are written therein: for the time is at hand.

Blessed is the person who reads/hears the prophecies of John[revelations] and follows/believes what is written for it will occur soon.

John to the seven churches which are in Asia: Grace be unto you, and peace, from him which is, and which was, and which is to come; and from the seven Spirits which are before his throne;

John wishes the seven churches which are in Asia well. The seven spirits are likely angels like Cherubs or Seraphs.

And from Jesus Christ, who is the faithful witness, and the first begotten of the dead, and the prince of the kings of the earth. Unto him that loved us, and washed us from our sins in his own blood,

John provides titles of Jesus and mentions the death and resurrection of Christ.

And hath made us kings and priests unto God and his Father; to him be glory and dominion for ever and ever. Amen.

John hopes Jesus will keep power over the world for eternity and speaks on how Jesus chose to make certain people kings/priests in the name of the father[in the respect of the father].

Behold, he cometh with clouds; and every eye shall see him, and they also which pierced him: and all kindreds of the earth shall wail because of him. Even so, Amen

John says Jesus will come with clouds, and all eyes[all people] will see him[Jesus] and all people will mourn this, even so, John says Amen[Let it be so]. Now, why would someone mourn? Well with his return comes the rapture. The time where those who follow him[those who are Christian] who still remain on Earth will return to him in Heaven. However, those who still deny him[those who aren't Christian] will stay on Earth. 

I am the Alpha and Omega, the beginning and the ending, saith the Lord, which is, and which was, and which is to come, the Almighty.

Jesus calls himself the Alpha[the first] and the Omega[the last], in summary, he was the first thing in the universe and is the last. He is just saying he is infinite[he is immortal]. 

I John, who also am your brother, and companion in tribulation, and in the kingdom and patience of Jesus Christ, was in the isle that is called Patmos, for the word of God, and for the testimony of Jesus Christ.

John calls himself the brother of Jesus, this may mean he was a great friend or cousin of him or that they are actual brothers. This is a debated topic.

I was in the Spirit on the Lord's day, and heard behind me a great voice, as of a trumpet, 11 Saying, I am Alpha and Omega, the first and the last: and, What thou seest, write in a book, and send it unto the seven churches which are in Asia; unto Ephesus, and unto Smyrna, and unto Pergamos, and unto Thyatira, and unto Sardis, and unto Philadelphia, and unto Laodicea.

There isn't much to say here.

 "And I saw between the throne (with the four living creatures) and the elders a Lamb standing, as if slaughtered, having seven horns and seven eyes, which are the seven spirits of God sent out into all the earth."

In this verse, John refers to Jesus as a lamb. "as if slaughtered" most likely refers to the resurrection on the cross. "Seven horns" Is metaphorical for his power. "seven eyes" represents the Holy Spirit's vision of everything on earth.

"4 And I heard the number of them which were sealed: and there were sealed an hundred and forty and four thousand of all the tribes of the children of Israel.

5 Of the tribe of Juda were sealed twelve thousand. Of the tribe of Reuben were sealed twelve thousand. Of the tribe of Gad were sealed twelve thousand.

6 Of the tribe of Aser were sealed twelve thousand. Of the tribe of Nephthalim were sealed twelve thousand. Of the tribe of Manasses were sealed twelve thousand.

7 Of the tribe of Simeon were sealed twelve thousand. Of the tribe of Levi were sealed twelve thousand. Of the tribe of Issachar were sealed twelve thousand.

8 Of the tribe of Zabulon were sealed twelve thousand. Of the tribe of Joseph were sealed twelve thousand. Of the tribe of Benjamin were sealed twelve thousand" (Revelations 7:4-8).

Very simply the Bible tells us 144,000 will be sealed or protected from the tribulation. See more here!

"And out of his mouth goeth a sharp sword, that with it he should smite the nations: and he shall rule them with a rod of iron: and he treadeth the winepress of the fierceness and wrath of Almighty God," (Revelations 19:15 KJV).

Out of Jesus' mouth comes a "sharp sword". This is interpreted by some as Jesus' speech acting as a weapon. The phrase "the sword of the Lord" normally refers to the word of God in the scriptures: "For the word of God is quick, and powerful, and sharper than any two-edged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and is a discerner of the thoughts and intents of the heart," (Hebrews 4:12 KJV). Also see Ephesians 6:17. This may mean Jesus with a mere word will win against his foes. Just as he creates life he too can bring it away just as easily.

In one commentary it states: "The sharp sword is the same that we have read of before (Revelation 1:16); there it was called the two-edged sword. The omission (or absence) of the epithet in this passage, which describes the Word of God as the conqueror and the judge, is not without significance. The sword is now wielded for but one work—the word that Christ spoke will judge men at the last day (John 12:48). The power of this word found an illustration in the falling back of the hostile band which came to take Him in the day of His humiliation (John 18:5); yet more gloriously will the power of His word be felt (comp. Isaiah 11:4; Jeremiah 23:29; 2Thessalonians 2:8) when He will slay the wicked with the word of His mouth," (Ellicot).

Another says: "I can easily agree that this two-edged sword is the word of Christ coming out of his mouth, but not the gospel, (the time was past for that, it was the time of the sacrifice in Bozrah), but his word of command, calling out his people to take vengeance upon the remainder of his enemies. The sword was both the sword of the Lord, commanding it to be drawn, and the sword of his people, whose hands were to wield it," (Poole).

Dr. David A. Falk too says: "Razor-sharp steel coming out of his mouth is not what is actually happening there. What's actually happening there is that God's voice is like a weapon. Christ's voice is like a weapon," (Falk).

Works Cited:

Dr. Falk, David. Live Stream #45: Live Stream #45: Ambulets and Rumors of Ambulets YouTube, YouTube, 12 Aug. 2023, https://www.youtube.com/live/K-auTwN2ygQ?si=uMdbDgIr2702Wzn4. Accessed 6 Dec. 2023.

Ellicott's Bible Commentary, Volume 1. N.p., Delmarva Publications, Inc., 2015.

Poole, Matthew. Matthew Poole's Commentary on the Holy Bible. United States, Hendrickson Publishers Marketing, LLC, 1990.

"The Spirit and the bride say, “Come.” And let the one who hears say, “Come.” And let the one who is thirsty come; let the one who wishes take the water of life without cost," (Revelations 22:17 NASB1995). 

The Spirit and the bride, that is: "here implied, the Church on earth, imploring her Lord about to come to her," (Cambridge). (C.f. Barnes & Jamieson).

The passage is very similar to what Jesus had previously said: "Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you: For every one that asketh receiveth; and he that seeketh findeth; and to him that knocketh it shall be opened," (Matthew 7:7-8 KJV) as well as when he said "Jesus answered and said unto her, Whosoever drinketh of this water shall thirst again: But whosoever drinketh of the water that I shall give him shall never thirst; but the water that I shall give him shall be in him a well of water springing up into everlasting life." (John 4:13-14 KJV).

The Holy Spirit and the church here call all to Jesus, urging all people to accept him. 

References:

Barnes' Notes on the New Testament. United Kingdom, Kregel Publications, 1962.

Jamieson, Robert, et al. Jamieson-Fausset-Brown Bible Commentary. United States, Hendrickson Publishers, 1996.

New American Standard Bible®, Copyright © 1960, 1971, 1977, 1995 by The Lockman Foundation. All rights reserved.

The Cambridge Bible for Schools and Colleges. United Kingdom, The University Press, 1905.