Not shemitta

'Mah inyan shemitta etzel har Sinai' is a malapropism. It should be 'Mah inyan sheviit etzel har Sinai' because the term shemitta never shows up in the laws that were said to be given at har Sinai. 

That error is a telling one because it reveals the presumption on the part of ChZl that the land belongs to the people and not to God, hence their need to shamet the land. I.e., the question reveals a profound misunderstanding of the essential covenantal character of the laws of sheviit – that the land is God's by choq and cannot be tranferred to Man.