佛說目連問戒律中五百輕重事經 1.38

1.38

問：「久遠故寺，都無垣障，不知佛地遠近。若欲作者，云何得知齊畔？」答：「不知當以意作齊畔，以不知故增損無罪。」

Question: "At an ancient, ruined monastery where there are no enclosures or fences whatsoever, one does not know the extent of the Buddha's ground. If one wishes to construct something, how can the boundaries be known?" Answer: "If one does not know, one should mentally establish boundaries; because one does not know, exceeding or reducing them incurs no offense."