What about prophecy in a church? Should the prophet ask the minister to check the word before it is given? Should a prophet first be 'released' into the ministry of a prophet before they are free to prophesy or give words in a meeting? If a person is on an organized mission and does not feel things are being done right, should they stay for the duration of the 'mission' or are they free to leave at any time? Is it right to do something other than what is commanded of the mission if the Holy Spirit leads an individual to do so, for example, the Spirit says to witness to someone but it may interfere with the set plans of the 'mission'?
It is tough trying to figure out how to start. There is so much that needs to be addressed in what initially looks like a simple set of questions. So, you may need to read this response in several ways to get at all the answers that you are searching for.
The duty of all members in a congregation is to check up on the word that anyone speaks in the name of God. In Acts 17:11 it says, "Now the Bereans were of more noble character than the Thessalonians, for they received the message with great eagerness and examined the Scriptures every day to see if what Paul said was true." Even though Paul had the power to do miracles, the Bereans were still commended for checking the Word to make sure that what he spoke was the truth. The duty to check the Word was not just the sole domain of someone designated as the "minister".
However, why would a prophet need to have someone check the Word before he was emboldened to speak? That almost sounds like the prophet is not completely convinced that he is a prophet. I have also never heard of the phrase "being released into the ministry of prophecy", so I have no idea what is entailed in such. I even did a search of the Internet and found that the phrase does not come up, so I am at a real loss as to what you might be referring to. I suspect that you may be working under the false assumption of what a prophet is. A prophet is a "spokesman for God". He speaks because the Lord tells him to speak. Deuteronomy 18:19 says, "If anyone does not listen to my words that the prophet speaks in my name, I myself will call him to account."
But it is just as easy to have a false prophet. God told the Israelites in Deuteronomy 13:1-5 "If a prophet, or one who foretells by dreams, appears among you and announces to you a miraculous sign or wonder, and if the sign or wonder of which he has spoken takes place, and he says, "Let us follow other gods" (gods you have not known) "and let us worship them," you must not listen to the words of that prophet or dreamer. The LORD your God is testing you to find out whether you love him with all your heart and with all your soul. It is the LORD your God you must follow, and him you must revere. Keep his commands and obey him; serve him and hold fast to him. That prophet or dreamer must be put to death, because he preached rebellion against the LORD your God, who brought you out of Egypt and redeemed you from the land of slavery; he has tried to turn you from the way the LORD your God commanded you to follow. You must purge the evil from among you." and Deuteronomy 18:21-22 "You may say to yourselves, "How can we know when a message has not been spoken by the LORD ?" If what a prophet proclaims in the name of the LORD does not take place or come true, that is a message the LORD has not spoken. That prophet has spoken presumptuously. Do not be afraid of him." Also in Jeremiah 28:9 "But the prophet who prophesies peace will be recognized as one truly sent by the LORD only if his prediction comes true." To summarize here, the tests for a false prophet are: 1) He speaks something that does not conform to the Scriptures and 2) any prediction he makes does not come true, especially if he predicts peace.
I make these points because many people think of prophets as men who get it right more often than they get it wrong. I have an uncle who thought he was a prophet. He even wrote a book -- absolutely convinced the Lord was speaking to him. However, very few of his prophecies came true. It was a hard lesson, but he eventually realized that he was not a prophet. I know that men today that call themselves prophets are not prophets. I know this because they fail the tests. Prophets today are quick to predict the end of the world. I haven't lived all that long and even in my short life, I have heard of dozens of end of the world predictions. Depending on who you listened to, the end was to come in 1983, 1987, 1990, 1993, 1995, 2000, 2001, 2007, and 2012. I have no fear of any of their messages because I know that they speak lies. I know they speak lies because what they say does not conform to what is in the Scripture. It is a tough standard to hold to -- 100% of all of your predictions must come true. God does not get it right "most of the time." God gets it right all of the time.
Additionally, I know that there are no prophets today because Paul said that after a time, there would be no more prophets. In 1 Corinthians 13:8-12 says, "Love never fails. But where there are prophecies, they will cease; where there are tongues, they will be stilled; where there is knowledge, it will pass away. For we know in part and we prophesy in part, but when perfection comes, the imperfect disappears. When I was a child, I talked like a child, I thought like a child, I reasoned like a child. When I became a man, I put childish ways behind me. Now we see but a poor reflection as in a mirror; then we shall see face to face. Now I know in part; then I shall know fully, even as I am fully known." The standard is that once the full (complete Word of God) is known, the partial (Word of God through prophecy) will disappear. Paul basically is saying that prophesy and tongues exist so that the complete Word of God could be made known. Once the complete Word is revealed, there will no longer be a need for prophecy.
In Hebrews 2:2-4, it says, "For if the message spoken by angels was binding, and every violation and disobedience received its just punishment, how shall we escape if we ignore such a great salvation? This salvation, which was first announced by the Lord, was confirmed to us by those who heard him. God also testified to it by signs, wonders and various miracles, and gifts of the Holy Spirit distributed according to his will." Unlike what many believe today, the purpose of the miracles was to confirm the Word. It was God's way of testifying that what was being preached was true. If we have the complete word today, what is left to confirm?
The closest thing in the New Testament that comes to an "organized mission" would be Paul's journeys as he preached the gospel in the Mediterranean area. At the beginning of one of the journeys Barnabas and Paul had a disagreement. Acts 15:37-38 records, "Barnabas wanted to take John, also called Mark, with them, but Paul did not think it wise to take him, because he had deserted them in Pamphylia and had not continued with them in the work." Evidently Mark's leaving the earlier trip bothered Paul, but it did not bother Barnabas. There is no indication that either side in this disagreement was right or wrong. Barnabas and Mark eventually went one direction and Paul and Silas another. So, if the disagreement is one of opinion, you are under no special obligation to stay with the group. That does not mean that you are not under a personal obligation because of commitments or promises that you made and are obligated to finish. You are not a slave to the mission work and the others in the group are not a slave to you.
However, if you are on a "mission work" and the mission is doing something that bothers your conscious, I believe you have an obligation to speak up and correct the wrong. If they won't listen, then you need to take action. I recommend following Jesus' instruction in Matthew 18:15-18 where it says, "If your brother sins against you, go and show him his fault, just between the two of you. If he listens to you, you have won your brother over. But if he will not listen, take one or two others along, so that 'every matter may be established by the testimony of two or three witnesses.' If he refuses to listen to them, tell it to the church; and if he refuses to listen even to the church, treat him as you would a pagan or a tax collector."
I am curious as to what type of mission work that you could be on where the leadership of the mission is adamant that you NOT speak. Are they fearful of a negative strong reaction? Have you personally demonstrated a lack of ability with the Scriptures? What is motivating them to silence you? If you truly have the Holy Spirit guiding you, then how is it that you choose to obey the leaders of your mission group rather than the Holy Spirit. Acts 4:19 says, "But Peter and John replied, "Judge for yourselves whether it is right in God's sight to obey you rather than God."
I have heard of some groups who, in the name of helping the poor, promise the government that they would not attempt to convert the people of the nation they are going into. If they are silencing you because the reason that you are on a mission is because of agreements they made, then why did you go? The only missions that Paul ever went on were to convert the world. There is no mention in the New Testament of mission work for the purpose of feeding the hungry or uplifting the downtrodden. Feeding the hungry and helping the downtrodden are works that Christians are expected to engage in, but such efforts are not referred to as mission work.
I believe that what you are interpreting as guidance of the Holy Spirit is more likely just the personal desires of your heart. Here is an easy test. Do you ever find yourself "speaking for the Holy Spirit" but then find yourself frustrated because someone points out a Scripture that you misused or a flaw in your logic that you can't defeat? If so, then what you are feeling is not the guidance of the Holy Spirit. The Holy Spirit does not make mistakes -- ever.