מדרש אויף מלכים א 19:8

(Devarim 1:2) "Eleven days from Chorev by way of Mount Seir to Kadesh Barnea": In eleven days they went from Chorev to Kivroth Hata'avah and from Kivroth Hata'avah to Chatzeroth and from Chatzeroth to the desert of Paran.

(Exod. 3:1, cont.:) AND HE CAME TO HOREB, THE MOUNTAIN OF GOD. R. Simeon ben Jose ben Leqonya said: Moses' flock went forty days without eating and without tasting anything, just as Elijah, of blessed memory, did. [It is so stated (in I Kings 19:8): ARISING, HE ATE AND DRANK. THEN ON THE STRENGTH OF THAT FOOD HE WENT FORTY DAYS AND FORTY NIGHTS UNTO HOREB, THE MOUNTAIN OF GOD.]

And came to the mountain of God, unto Horeb (Exod. 3:1). R. Simeon the son of Yosé maintained that Moses’ flock roamed about for forty days, and that, like Elijah of blessed memory, he tasted no food (during this time), as it is said: And he arose, and he did eat and drink, and went in the strength of that meal forty days and forty nights (I Kings 19:8). And he led the flock to the farthest end of the wilderness (Exod. 3:1). This informed him that (the older generation of) Israel, which was called the flock, would perish in the wilderness.