I thought the book of revelation is written for ALL believers?
God's wrath =/= tribulation.
Paul wrote all his letters to Gentiles and Jews (who were saved through Paul's gospel of uncircumcision (Gal. 2:7-9) after God cut off Israel. When God cut off Israel and bypassed Israel and went directly to the Gentiles with Paul (the apostle to the Gentiles), there was no longer any distinction between Jew or Gentile, male or female, slave or free. Prior to Paul, if a Gentile wanted to approach Israel's God, he had to get circumcised and keep the law of Moses and do good works. When a female was born to a Jewish father or married a Jewish man, she was automatically under the Abrahamic Covenant of Circumcision or law. If a slave was bonded to a Jewish man, he was under this covenant as well. When a Jewish male got circumcised on the eighth day of his life, he was automatically under this covenant. Jesus came, was circumcised, and voluntarily put Himself under His own law--and kept it perfectly. But what Paul is saying is that we do not have to go through Israel's Abrahamic Covenant; we "come boldly to the throne of God" as individuals of His Body. Where God dealt with Israel as a nation (corporate relationship), our citizenship as a member of His Body is international.
All the circumcision apostles (John, James, Matthew, Mark, Luke, James are written to the nation of Israel. (And of course Jesus "came only to the House of Israel." Circumcision, Sabbath law, certain feasts are perpetual, everlasting, as long as there is an Israel. Contrast this with Paul who tells us we don't have to do any of these things: "If you get circumcised, Christ will profit you nothing."
Many Christians mistakenly think that after the Cross, Israel was no longer under Sabbath law or circumcision. But this is untenable considering that these laws were perpetual for Israel and carried a death penalty for disobedience to any one of them. Jesus warned, talking of the Tribulation to come, "Let your flight be not on the Sabbath..." after the Cross. And while Paul taught that we could eat meat sacrificed to idols, Jesus warned Jews in the seven churches of Asia (Rev. 1:4) that hey had better not eat meat sacrificed to idols (Rev. 2:14). And God makes it clear that He is talking to Israel in verses such ass Rev. 3:9.
Revelation can't be written to members of the Body of Christ. Why? Because we will be in heaven. Our citizenship is in heaven. Israel's is on earth.
Yes, "the wrath that is to come" is the Tribulation or the time of Jacob's trouble. Recall that when the Pharisees came to John the Baptist while he was baptizing Jews and proclaiming the coming of the Messiah he said to the Pharisees: "Brood of vipers! Who warned you to flee from the wrath that is to come? A careful study of the Daniel weeks prophesy will show that Jesus was to come to Israel at a certain date. Then He would be cut off for His people (Israel) and go to the Father for approximately 7 years. During those 7 years, Israel would go through their Tribulation and Jesus would come back and set up His kingdom for Israel with Jesus sitting on King David's throne in Jerusalem. But, and this is a big but, all was contingent on Israel accept their risen Messiah. A careful reading of the first half of Acts shows that Israel was starting into their Tribulation (for which Jesus prepared them) and the Twelve were trying with every fiber of their body to convince Israel to accept their risen Messiah "so that the Father would send Jesus back" (Acts 3:20). But, alas, Israel rejected their risen Messiah and God, patience exhausted, cut Israel off.
If there are any thing I said that you want me to back up with Scripture, let me know.