When the 1662 Book of Common Prayer was adopted in England, about 20 per cent of the ministers of the Church of England resigned and many lay people left the Church.
If we were in a similar situation, would we stay or would we go? Inevitably there will be some who stay and some who decide to leave a church in every age. How then should we cope with this with Christian maturity? 
For Those Planning to Leave
Do Not Leave For Trivial Reasons
Separation is a serious matter, and for leaders to separate is even more serious, because we are judged with greater strictness, and our actions influence others to a greater extent. It would be a great sin to excuse your leaving by claiming that your church or denomination is no longer part of the church of Jesus Christ, when it is. Paul’s instruction to ‘go out from their midst' (2 Corinthians 6:17) is not an instruction to leave a corrupt church or denomination, but to avoid being contaminated with idolatry in the world. Unnecessary schism is a sin.
Leave For Good Reasons
A. You are no longer able to endure the sins and weakness of the church or denomination
It is possible to believe that a church or denomination is still part of the church of God, but also to that you can no longer bear to live with its sins and weaknesses.
If you find the sins and weaknesses of your church or ministry highly offensive, then you must either learn to be gracious and patient or you could consider leaving for another context of ministry.
We should all make sure that we know the characteristic sins of our church, denomination or organisation, and lament them, work and pray to bring about repentance and change, oppose them and oppose those who perpetrate them, call those who allow them to account, and pray for God’s mercy and transforming grace.
B. There is mission and ministry to be done that cannot be done by this church or denomination
William Carey was right to challenge Christians in England to work to bring the gospel to people around the world, and he was right to recognise that this could not be done without a ‘means’, that is, an organisation to achieve that purpose.
He wrote his Enquiry Into the Obligations of Christians to use means for the Conversion of the Heathens, which led to the founding of the Baptist Missionary Society in 1792. This was a recognition that local churches could not do world mission by themselves: a ‘means’ was needed.
To Think About Before You Leave
Do not leave because distant fields look greener! We feel the pressures of our present situation, and cannot yet imagine the pressures we will endure in a different situation. And realise that the parting of friends is always painful, and there are costs for everyone.
Present gospel bonds must be weakened if you move to a new context of ministry and the two great costs of ministry are first of all investing in building relationships, and then extracting yourself from them.
If you are going to leave a church or denomination or association, look for an existing ministry, association, or denomination, rather than creating a new one. If you must go, then go in sorrow rather than in pride.
If You Decide to Stay
Is it possible to stay in a church or denomination and reform and renew it? Yes, with sufficient resources, patience, flexibility, prayer and dependence on God, and a long-term plan.
The keys to doing this include, making necessary changes, and letting your denomination catch up eventually. Most reforming movements begin ‘from below’, and the leaders of the denomination and the denomination as a whole catch up eventually.
Make sure that you distinguish between matters of primary importance and matters of secondary importance, and focus your attention on primary matters.
Of course, you will be urgent for change. But recognise that God is patient with you and your sins, and show the same patience with others. Remember that it takes many years to change a church from its former ways, and decades to change a denomination.
Reform Your Church By the Bible
We always need to be reformed by the Word of God, and all our churches, ministries, associations, and denominations always need to be reformed by the Word of God. This need will continue until the day of Christ’s return. So whether we stay or leave, we will always have this responsibility.
 This is an adapted excerpt from Peter Adam, ‘Gospel Trials in 1662: To Stay or To Go?’ St Antholin’s Lectureship Charity Lecture 2012 (Latimer Trust: London, 2012), 59-65.