Anyone know who among Buddha's disciples used to be mara, but
later vowed to protect Buddhadharma? And mara
normally don't vowed. See how they are reformed by Buddha!

for reference:
Thus I have heard, at one time the Buddha dwelt at Shravasti, in
the Jeta Grove in the Garden of the Benefactor of Orphans and the
Forlorn, together with a gathering of Great Bhikshus,
twelve-hundred fifty in all, all Great Arhats well-known to the
assembly: Elders Shariputra, Mahamaudgalyayana, Mahakasyapa,
Mahakatyayana, Mahakausthila, Revata, Suddhipanthaka, Nanda,
Ananda, Rahula, Gavampati, Pindola-Bharadvaja, Kalodayin,
Mahakaphina, Vakkula, Aniruddha, and others such as these, all
Great Disciples, together with all the Bodhisattvas, Mahasattvas:
Manjushri, Prince of Dharma; Ajita Bodhisattva, Gandhastin
Bodhisattva, Nityodukta Bodhisattva, and others such as these, all
Great Bodhisattvas, and together with Shakra, Chief among Gods, and
the numberless great multitudes from all the heavens. - Amitbha
sutra
thanks,
Amtf.
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