Why does the Torah repeat "Al Pi Hashem Yachanu, ve'Al Pi Hashem Yisa'u ... "?
Seforno: To teach us that Yisrael followed instructions whether they encamped for an inconveniently short period or whether they traveled after they had encamped for a long time and were comfortably settled. 1
It is not clear however, what the Torah is saying that it has not already said in Pasuk 20. (EC)