Because the fourfold ministry was necessary to perform the full services of the liturgy, four priests, one of each border, had to be present along with the bishop. The border could be defined for any person or minister; thus, there were combinations of rank and border in any manner. For instance, there were angel-prophets, angel-evangelists, and priest-prophets as well as priest-elders, deacon-pastors, deacon-prophets, and so on. Certain of these combinations often implied particular roles. For example, the angel-evangelists were particularly responsible for evangelism within their geographical region or tribe while angel-prophets were automatically at the disposal of the apostles in Albury.