大般涅槃經義記 6.151

6.151

'One who sees the buddha-nature' himself seeks to realize it; intending to undertake this matter, one must first purify one's body. Second, because the body is purified, no one will ridicule or scold. Third, because no one scolds, they will revere, have faith, and arouse the [bodhi] mind. The Tathāgata concludes with praise: 'is then a good spiritual friend to sentient beings', etc.; from 'this is called' downward, it concludes how this is distinct from the worldly.