Oh my goodness . . .
Shemittah is mentioned plenty of times in the Torah. It's the Hebrew word (the Torah is written in Hebrew, you know) usually translated "sabbatical year" in KJV English.
Now as far as that "sabbatical year" goes, do you have English language New Testament verses that point to evidence that I as a Christian should be at all concerned with it? Were Christians in the New Testament, put under some sabbatical law that perhaps I should be made aware of?