Puggalapannatti 2.4.114.3

2.4.114.3

So dhammaṃ deseti ādikalyāṇaṃ majjhekalyāṇaṃ pariyosānakalyāṇaṃ sātthaṃ sabyañjanaṃ, kevalaparipuṇṇaṃ parisuddhaṃ brahmacariyaṃ pakāseti.

He teaches the Dhamma good in the beginning, good in the middle, and good in the end, with meaning and phrasing; he explains a spiritual life completely fulfilled and entirely purified.