Deuteronomy 19:14

(14) Thou shalt not remove thy neighbour’s landmark.—Another law manifestly appropriate here, where it appears for the first time, like the “field” in the tenth commandment (Deuteronomy 5:21). But the immediate connection is not obvious. Perhaps the idea is to caution the people to avoid a most certain incentive to hatred and murder. Ancient landmarks are also important and almost sacred witnesses.

They of old time.—The first dividers of the land. There is no idea of antiquity about the expression.