A monk asks a fellow-monk as to when a monk’s insight is said to be fully purified. When he really understands the arising and the passing away of the six-fold sense sphere answers the other. Not being satisfied, the first monk asks others who, in turn, declare in similar terms of the five aggregates of attachment (upādānakkhandhā), the four primary elements (mahābhūta), etc. Finally he asks the Buddha, who says that the answers of the monks were like those of men who, on being asked what the Judas tree (kiṃsuka) was like, describe it, not as it really is, but as each one of them happens to have seen it. The Buddha explains the monk’s question by means of the parable of a city, strongly guarded, having six gates and a watchful warden of the gates, receiving messengers from various quarters (S.iv.191 ﬀ). Cf. Kiṃsukopama Jātaka.