Hi this is a Christian Tradition founded by Jesus Christ before his death that is supposed to be celebrated yearly in remembrance of his death and what it means for mankind’s future, Luke 22:14-20. This is normally observed during Easter as a holiday. In Judaism it is called the Passover and is celebrated yearly and is still observed in its original form. Even though Christianity has been embraced by the entire world which shows modern religious principles that originate with and from God, there are still many people worldwide that reject Jesus Christ as the Messiah.
There are many questions that you have asked, and each question shall be answered. (1. Is this a marriage of the Lamb? No, the Kingdom was foretold to have a feast at its establishment. Once the invitations were rejected by people considered chosen ones a replacement was conducted, Matthew 22:1-14. Your question, however, is implied towards the observance of the death of Christ and its significance for the future of mankind as Good News for people everywhere on earth. It can be plainly seen at Luke 22:14-20. The Lord’s anniversary of his death will always be remembered even in the Kingdom of God the Lord’s supper will be performed every year forever, Revelation 3:19-20.
(2- How will the saints or the Chosen Ones reside in the Kingdom of God? The Chosen Ones are picked individually by God and will inherit the kingdom with an invitation only, Matthew 25:31-46. The joy or rapture is felt since the Kingdom of God is for the earth and focuses on people that are chosen to live there, Psalms 37:11. Once they are “gathered” from all the earth together or acknowledged as approved during the Second Coming of Christ, Revelation 7:13-17. They will work towards transforming themselves to become the Sons of God the New Jerusalem that is promised for them, Isaiah 2:2-4. The marriage feast is the invitation to come and celebrate their inheritance with its expressions recorded at Revelation 21:5–8. The Chosen Ones are also recoded at Revelation 14:1–5.
(3- Are the chosen Ones or Saints gathered before the Great Tribulation? People have always worshipped God in various forms everywhere. The Lord Jesus Christ was written in the Scriptures as the correct way to worship God. This happened long before the Great Tribulation came with the Second Coming of Christ. As shown in the parable of the Wedding Feast these people rejected the invitation when the Kingdom of the Heaven was established, Matthew 22:1-14. In the modern era the Great Tribulation arrives at the Second Coming of Christ as extreme weather occurrences the chosen ones survive the tribulation since all must confront the test of the whole earth, Revelation 7:9–17. The information in Revelation 7:15 explains that they are before the throne of God and agree that God is righteous in judgment that makes them worthy to enter the Kingdom of God, Revelation 20:11–15.
