The Ark containing the "Tablets of the Law" was the most secluded of
the Mishkan's vessels, hidden away in its innermost chamber, the "Holy of
Holies." This expresses the ideal that the Torah scholar (who serves
as an "Ark" for the Torah) must remove himself from all worldly
endeavors. At the same time, the Ark was also the most "portable" of the
Tabernacle's vessels. The Torah decrees that, "The carrying
poles shall be in the rings of the Ark; they shall never be removed
(Exodus 25:15) -- a law which applies exclusively to the Ark.
If there is a soul somewhere in the ends of earth thirsting for the word of G-d,
the Torah scholar must be prepared to leave his sanctum to transport the Torah to
that place. Even as he sits in his "Holy of Holies," he must be always at the ready to venture out,
constantly aware of his responsibilities toward the world outside.
(The Lubavitcher Rebbe)