註四十二章經 1.258

1.258

有沙門夜誦經，其聲悲緊，欲悔思返。佛呼沙門問之：「汝處于家，將何修為？」對曰：「常彈琴。」佛言：「弦緩何如？」曰：「不鳴矣。」「弦急何如？」曰：「聲絕矣。」「急緩得中何如？」曰：「諸音普調。」佛告沙門：「學道猶然。執心調適，道可得矣。」

There was a śramaṇa who chanted sūtras at night; his voice was mournful and strained, and he wished to repent and return [to lay life]. The Buddha called the śramaṇa and asked him: "When you were at home, what did you practice?" He replied: "I often played the lute." The Buddha said: "What if the strings are slack?" He replied: "It will not sound." "What if the strings are tight?" He replied: "The sound snaps." "What if they are neither tight nor slack, but balanced?" He replied: "All notes are universally harmonious." The Buddha told the śramaṇa: "Learning the Way is just like this. If you hold your mind in balanced harmony, the Way can be attained."