Ministry surely can't be done without faith -- in the sense of walking by faith in God. I sense that there are three "levels" of faith in ministry.
• The lowest level would be faith that things will work out the way that one expects them to. But that is hardly "faith", and it is not helpful when things go wrong.
• The next level up is faith which one has learnt from Scripture, or from experience -- faith which applies where a human solution isn't clear, or isn't there. This is obviously greater, yet may not be of much help in less familiar territory -- perhaps scary territory.
• I think the highest level of faith is faith in spite of -- faith which trusts in a sovereign God, absolutely, totally, unconditionally. One finds such faith often in the Bible. I think that every minister will need it at some stage.