The last book in the Bible is about God's message to all of mankind of what is to come. Interestingly enough, the Bible starts off in Genesis with "The Tree of Life" and ends with the same "Tree of Life" in Revelation.
God sends The Angel to share his message and this Tree of Life is reintroduced as our means to eternal life. Here we see prophesy and God's promises fulfilled. We are left with hope because despite reading all about the coming suffering and judgments ahead of us, we can always count on the proverbial "Light at the end of the Tunnel", which is GOD. That is what we are walking towards, so if we can keep that in our focus, walking daily with him and not dwell in all the other challenges we are faced with, our future will be set and we will be rewarded with eternal life.
Chapter 22 ends with the title JESUS IS COMING. Throughout the Bible GOD warns the world of Jesus' imminent return by giving plenty of advance notice to all before his wrath is unleashed (think of the warnings through Noah or Abraham regarding Sodom and Gomorrah) and he did this to give everyone time to repent and to be ready to receive him and have eternal life with him. We should not forget that as Christians, we are all going to be with Jesus Christ as believers and the way we live our lives here on earth, may very well determine just how we will reign with the Lord. He gave us free will, he died for our sins, he desires for us to commit our lives to holiness.
Jesus came to us the first time as an expression of GOD's love and he came to die for our sins. But the Bible says that when he returns, he will come in vengeance to pour out the wrath of GOD on those who have rejected GOD's love and grace. The good news is, there is still time for all to receive Jesus Christ as Lord and Savior before his return. If you haven't done so yet, it's not too late.