Some years ago someone explained to me a passage which I believe was
in the Pali Canon where mindfulness is compared to a gatekeeper whose
job is to refuse entry to suspicious characters, and only allow
trustworthy people to enter the town. In a similar way, mindfulness
enables us to be watchful over our senses and not allow impressions
to develop into harmful thoughts. I liked this simile very much. Does
anyone know where this passage is located? I've been trying to find
it without success. Thanks in advance for any assistance.