四分律刪繁補闕行事鈔 1.402

1.402

丈夫者。必以建心慕遠，清節不群；卓然，風霜不改其操；鏗然，憂喜未達其心，便為丈夫之貌。故律云：年二十者，方堪受具。謂能忍寒熱、飢渴、風雨、蚊虻、毒蟲，能忍惡言苦事，能持戒，能一食等。《僧祇》云：若過二十，減七十，無所堪能，不應與受具。

Regarding a manly person (puruṣa): One must establish one's mind to aspire to what is lofty, with pure integrity that stands apart from the crowd; outstanding, so that wind and frost do not alter one's conduct; unyielding, so that grief and joy do not penetrate one's mind—this constitutes the appearance of a manly person. Therefore the Vinaya says: Only when one is twenty years of age is one capable of receiving full ordination. That means being able to endure cold, heat, hunger, thirst, wind, rain, mosquitoes, gnats, and poisonous insects; being able to endure harsh words and painful matters; being able to uphold the precepts; being able to take one meal a day, and so forth. The Mahāsāṃghika-vinaya says: If one is over twenty and under seventy, yet has no capabilities whatsoever, one should not be granted full ordination.