The Book of Numbers describes the layout of the tabernacle and the encampment in the wilderness.  The tabernacle faced eastward toward the rising of the sun.  If you were to go inside of the tabernacle and look out to the east you would see Moses (the prophet), Aaron and his sons (the priest), the tribe of Judah (the king) and the sun.  Could it be that from God's viewpoint in the tabernacle He saw the future work of the Son of God?  Jesus Christ is the prophet, priest and king and according to Malachi 4:2But unto you that fear my name shall the Sun of righteousness arise with healing in his wings; and ye shall go forth, and grow up as calves of the stall.
See All..., He is the "Sun of righteousness".  In addition to this we can see that the work that Jesus did during His earthly ministry was that of a prophet.  In His death, burial and resurrection, He preformed His priestly work.  When He comes again in Revelation 19, He will be coming as a King establishing His throne and when He is ruling and reigning, truly, He will be the "Sun of righteousness" with healing in His wings.