Mahasunnatasutta 4.2

4.2

Yo ca kho so, ānanda, bhikkhu eko gaṇasmā vūpakaṭṭho viharati tassetaṃ bhikkhuno pāṭikaṅkhaṃ sāmāyikaṃ vā kantaṃ cetovimuttiṃ upasampajja viharissati asāmāyikaṃ vā akuppanti—ṭhānametaṃ vijjati.

But it is possible that a mendicant who lives alone, withdrawn from the group will enter and remain in the freedom of heart—either that which is temporary and pleasant, or that which is irreversible and unshakable.