This was said by the Blessed One, said by the Arahant, as I have heard:
“Bhikkhus, abandon one thing; I am your |guarantor::assurer, security [pāṭibhoga]| for |non-returning::third stage of awakening where the lower five fetters of 1) personal existence: view that one is an embodied being, 2) doubt, perplexity, or indecisiveness, 3) adherence to rules and observances, 4) sensual desire, and 5) ill will are completely overcome [anāgāmitā]|. What one thing? Bhikkhus, abandon |anger::rage, wrath, fury, indignation [kodha]|; I am your guarantor for non-returning.”
The Blessed One spoke on this matter. In this regard, it is said:
“When overcome by anger,
beings go to a bad destination;
Fully understanding anger,
those seeing clearly abandon it;
Having abandoned it, they do not come again,
to this world at any time.”
This matter too was spoken by the Blessed One, as I have heard.