Rabbi Hiyya bar Abba taught in Johanan bar Nappaha's name that the words of , "You shall not remove your neighbor's landmark, which they of old have set," meant that when planting, one should not encroach upon the boundary that they of old set. (Thus, one should not plant so near to one's neighbor's border that one's plants' roots draw sustenance from the neighbor's land, thus impoverishing it.) The "Gemara" further cited this analysis for the proposition that one may rely on the Rabbis' agricultural determinations.