From In One Body Through The Cross: The Princeton Proposal on Christian Unity

71. The disciplines of unity are penitential. As St. Paul teaches, for the sake of unity we must be willing to suspend gospel freedom and conform to the limitations of the weak. This process will ascetical; it will necessarily involve the sacrifice of real but limited goods for the sake of greater good. We are convinced, however, that this ascetical dimension is necessary if the ecumenical project of modern Christianity is to move forward. Unity will require our churches not only to renounce the selfishness and insularity that we all dislike and easily see as sinful. It will also require our churches to embrace a spiritual poverty that has the courage to forego genuine riches of a tradition for the sake of a more comprehensive unity in the truth of the gospel.