Does the Church of God need to reunited into one group or organization in order to do a powerful work of preaching the gospel to the world and the Ezekiel warning to Israel?
No, and I think there is Bible evidence and evidence from our history that we will NOT unite into one group before the return of Christ. Yet, I believe, and am hopeful, that a powerful work will be done by the Church before the tribulation begins.
Why will we not unite?
The last era of the Church of God is Laodicea. But the Philadelphia era is promised protection and is given an open door for preaching the gospel to the world, which has yet to be completed with power. This means that right before the tribulation begins, there will be both Laodicean members and Philadelphian members in the Church of God, with Laodiceans being the majority and Philadelphians being relatively small in numbers. The Philadelphians are given an open door and they complete the preaching of the gospel to the world and the Ezekiel warning to Israel as a witness, and then God sends them to a place of safety for protection from the tribulation. The Laodiceans then go through the tribulation (Revelation 3:7-22).
Will Laodicea and Philadelphia be reunited into one group? I doubt it. They are too different. Read the descriptions in Revelation and ask, do these messages describe people that will unite with each other and function harmoniously?
Part of the reason the Church is scattered and divided now is because the Laodicean attitude is the predominant attitude in the whole Church of God. Laodicea is the last era, and that means they will be the majority right up to the end. Yet, they are still part of the true Church of God.
Rather, I think Philadelphian Christians will be more effective and more powerful when they are NOT merged with Laodicean members of the Church. Sometimes separation is better than unity if unity means being forced to compromise with a Laodicean majority (2 Corinthians 6:17).
Some think that the Church must reunite before we can do a powerful work because they are looking at the SIZE of the Church, not the spiritual condition. They are looking at human power, not God's power, to do the work.
But that is false reasoning. God did more with Gideon's army when it was small than when it was large because God wanted to show HIS power to do a powerful work with limited human instruments. God made Gideon limit his army to only 300 men before God used him. There may be a lesson for us today (Judges 7:1-7).
Besides, when it comes to human power, we don't have the power to warn 400 million people about the tribulation even if we are united. If you put all the Churches of God together, you would not have the numbers we had when Mr. Armstrong was alive, and even at that time we could only reach a small number of people with the true gospel.
We have to rely on God's power, and God will make that power available to us based on our faithfulness and zeal to believe and obey Him, not on numbers. It is the Philadelphians that will be given that power, not the majority of the Church of God, not Laodiceans.
I do not think the Church of God will unite into one organization before the return of Christ. If anything, there will be more division as God separates Philadelphia from Laodicea in preparation for Philadelphia finishing the work and going to a place of safety.
"Do not think that I came to bring peace on earth. I did not come to bring peace but a sword. For I have come to 'set a man against his father, a daughter against her mother, and a daughter-in-law against her mother-in-law'; and 'a man's enemies will be those of his own household' " (Matthew 10:34-36).
Each of us needs to strive to be faithful to God, to be Philadelphians in spirit, attitude, and character, and then God, in His time and in His way, will gather us together, separating us from the Laodiceans, to finish preaching the gospel to the world and the Ezekiel warning to Israel as a witness and then go to a place of safety before the tribulation begins.
And even when Philadelphia is separated from Laodicea and given power by God to finish the work, they may not be part of one organized, incorporated fellowship of the kind we tend to see today. It could be two organizations, or three, or maybe just one. BUT, if it is more than one organization, those organizations will cooperate with each other in harmony and love, as much as if they were one organization. Just as Peter and Paul had separate administrations, yet cooperated with each other in dividing up the responsibilities (Galatians 2:7-9, 2 Peter 3:15), so Philadelphians, even if making up more than one corporation, will cooperate with each other and not compete with each other.