Parshah Bamidbar - Numbers 1:1-4:20

And G-d spoke to Moses in the desert of Sinai (Numbers 1:1)

The Torah was given to the people of Israel in the ownerless desert. For if it were given in the Land of Israel, the residents of the Land of Israel would say, "It is ours"; and if it were given in some other place, the residents of that place would say, "It is ours." Therefore it was given in the wilderness, so that anyone who wishes to acquire it may acquire it.

(Mechilta D'Rashbi)