What is an apostle really? ... It is difficult even to consider them "great religious personalities," if by this we mean bearers of inherent spiritual talents. John and Paul were probably exceptions, but we only risk misunderstanding them both by overstating this. On the whole, we do the apostle no service by considering him a great religious personality. This attitude is usually the beginning of unbelief. Personal importance, spiritual creativeness, dynamic faith are not decisive in his life. What counts is that Jesus Christ has called him, pressed his seal upon him, and sent him forth. ... It is not he who speaks, but Christ in him.
Romano Guardini, The Lord