The opposite of serving with confidence is serving in faith or with faith. A person who serves God without having the vision is a person who serves in a natural way with much confidence. Those who are naturally strong in themselves do not need faith. Actually, a natural person cannot have faith; he has confidence instead of faith. But when we have the vision, we serve God not with confidence but with faith and in faith.
The opposite of serving enthusiastically is serving fervently. One who serves God fervently is not enthusiastic in himself but is fervent, inwardly burning in the Holy Spirit.
Now we need to ask, What is the opposite of serving God with a purpose? Instead of serving with a purpose, we should serve by the Lord's guidance. Whenever we do something with a purpose, we are behaving like a politician. Politicians always do things with a definite purpose. The more we act with a purpose, the more political we are. If we do not have the Lord's guidance to go to a particular place, yet we go to that place with a definite purpose, we are serving naturally and religiously.
Suppose you are going to the Far East. If you are going there with a definite purpose, you are going there as a politician. If you are asked why you are going to the Far East, you should be able to say, "My going to the Far East is of the Lord's guidance. I am not going there to accomplish a certain purpose. Rather, I am going to the Far East according to the Lord's guidance."
It is hard to discern guidance from purpose. You may say that when you have the guidance you have the purpose. Even if this is the situation, you need to act not according to the purpose but according to the guidance. In the book of Acts the apostles, the sent ones, went out, but it is difficult for us to see what their purpose was in going out. They went out by the Lord's guidance. They had no purpose, but they did have the Lord's guidance. Consider the example of Philip in Acts 8:26-39. The Holy Spirit guided him to contact the Ethiopian eunuch (v. 29). Philip did not have a purpose; he simply had the Lord's guidance. Before Philip contacted the eunuch, Philip had no idea concerning what would happen. His contacting the eunuch was not with a purpose; it was by the Lord's guidance.