A priest is given responsibility for spiritual things. In the dream, he often represents the authority figure in whose hands the dreaming has taken control of his life.
When a priest emerges in the dreamer's dream, it usually testifies to his awareness of the more spiritual, knowing side of his self. Ancient Egyptian dream researchers believed that seeing a priest in the dream would soon earn you an honorable post.
A priest is a man of God, and perhaps the dreamer must realize that there is much to be learned for him on the material level as well as the spiritual level.