Worship Elements: Preaching: Redundant Gospel? (1 Cor. 1:18)

We might think that we know the Gospel and we know the Gospel well.  So, why would we think that we need to continually hear the Gospel preached if we know the Gospel message?  Is there a point in our Christians lives when we move beyond the Gospel message?  What wisdom can be gleaned from church history that would shed some light on this issue of Gospel preaching?