|Art Baruch Nachshon|
''From there, they journeyed to Gudgodah, and from Gudgodah to Yotvath..'' [Eikev 10:7]
Rashi: And at Moserah, you made a great mourning for the death of Aaron, which was the cause of this [your retreat], and it seemed to you as though he had died there. Moses juxtaposed this reproof with the breaking of the tablets to indicate that the death of the righteous is as grievous to the Holy One, blessed is He, as the day the tablets were broken...
Why is a tzadik [Aaron] compared to the tablets?
The writing on the tablets represented the ''soul'' of the tablets, and the tablets themselves, their ''body''. The fact that the Ten Commandments were engraved into the tablets, and not merely written onto them, means that the words and the tablets [''soul'' and ''body''] became one single, indivisible entity.
Likewise in the case of a tzadik, it is not merely that his soul interacts with his body, but that the tzadik's physical life is totally at peace with his soul such that ''the life of the tzadik is not a physical life, but a spiritual life''.
Based on Likutei Sichos vol 14 pp 32-34 Lubavitcher Rebbe