Quickly

A moutain path, if often used, will quickly become a road. If it is not used, it will soon become blocked up with sprouting grass and weeds. This is so for the human heart too.
The Third Year of Ansei, the Seventh of June. “Minutes of the Head Lecturer.”

17日倏忽の間なり
山径の蹊間は、是れを用ふれば其の路を成すこと倏忽の間なり。又用ひざれば茅草生じて是れを塞ぐことも亦小頃の間なり。人の心も亦然り。
安政三年六月七日「講孟箚記」