(Bamidbar 10:35) "And it was, when the ark traveled": There are signs (inverted nuns) before (this verse) and after (the next verse). Rebbi says: Because it is a book in itself — whence they ruled: A (Torah) scroll which was erased, and there remained eighty-five letters, as in the section "And it was, when the ark traveled" (imparts tumah to the hands [a Rabbinical enactment, viz. Shabbath 14a]).
R. Shimon says: There are signs before and after because this is not its place. What should have been written? (Bamidbar 10:33) "And they traveled from the mountain of the L-rd, a journey of three days. (And the ark of the covenant of the L-rd preceded them a distance of three days"). (Bamidbar 11:1) "And the people were as seekers of a pretext." An analogy: Some men say to the king: Would you please accompany us to the governor of Acco?
They arrive at Acco — he has gone to Tyre. They arrive at Tyre — he has gone to Tziddon. They arrive at Tziddon — he has gone to Antochia. They arrive at Antochia — some of them start complaining against the king for having put them to all of this trouble!
It is the king who should complain, for having been put to all of this trouble for their sakes! Similarly, on that day the Shechinah traveled a three-days journey, so that they could (immediately) enter Eretz Yisrael — and they began to complain before Him for having been put to all of that trouble! It is He (if anyone) who should have complained! For it was for their sakes that the Shechinah was thus constrained!