Vedavyasasmriti 42

42

keśāntakarmmaṇā tatra yathoktacaritavrataḥ .
samāpyavedān vedau vā vedaṃ vā prasabhaṃ dvijaḥ .
mrāyīta gurvanujñātaḥ pravṛttoditadakṣiṇaḥ .. 1.41 ..

having observed the vow as prescribed, through the first shaving ritual at that time, / having completed the Vedas, or two Vedas, or one Veda with diligence, a twice-born / should bathe, permitted by the teacher, having offered the prescribed teacher's fee. // 1.41