佛說目連問戒律中五百輕重事經 1.104

1.104

問：「一人靜處得結坐不？」答：「先有結界，二人以上得。一人以不得，無人共受坐故。無界盡不得。若欲別坐，當更請僧結界，坐然後得。」

Question: "May a single person enter the retreat in a quiet place?"
Answer: "If a sīmā was previously established, two or more people may. A single person may not, because there is no one with whom to enter the retreat together. Where there is no sīmā, none of them may. If one wishes to sit separately, he must further invite the saṃgha to establish a sīmā, and only after entering the retreat may he do so."