"Theology is thinking what to say to be saying the gospel. Like every intellectual enterprise, this demands its own appropriate practices of thought. Since the gospel is whatever the apostles said to say, "Jesus is risen," apostolic reflective activity also - however profoundly or superficially done - must have been the right sort of thing to be doing.
"Theology... may be described as the historically continuing discussion and debate internal to the mission of the gospel. Apostolic theology is the founding beginning of this dicussion.
"Theology is a continuing argument between different and sometimes incompatible proposals, and presumably always will be. If the theology of the apostolic church were uniform, it would be less available to us."
(Robert Jenson, Systematic Theology vol.1, p.32-33. Italic original.)