it is the banner of the Arahants and enables them to be devine messengers (the messenger of the path the fourth the Buddha encountered as a Prince before he left the household life).
It also physically embodies the homeless life, making a separation between spiritual seeker and those living the life of the householder.
“Mendicants, these two [types of persons] defame the Tathāgata.
(The mendicants asked) What are the two [types of persons]?
(The Lord Buddha responded) The malicious, or the inwardly angry, and the one with (blind) faith or the one who holds things incorrectly.
Mendicants, these two [types of persons] defame the Tathāgata.”
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"Others will misconstrue reality based on personal perspectives, firmly holding onto and not easily discarding them; We shall not misconstrue reality due to our personal perspectives, nor firmly holding them, but easily discarded."