Nandasutta
Evaṁ me sutaṁ— ekaṁ samayaṁ bhagavā sāvatthiyaṁ viharati jetavane anāthapiṇḍikassa ārāme. Tena kho pana samayena āyasmā nando bhagavato bhātā mātucchāputto sambahulānaṁ bhikkhūnaṁ evamāroceti: “anabhirato ahaṁ, āvuso, brahmacariyaṁ carāmi; na sakkomi brahmacariyaṁ sandhāretuṁ, sikkhaṁ paccakkhāya hīnāyāvattissāmī”ti.
With Nanda
So I have heard. At one time the Buddha was staying near Sāvatthī in Jeta’s Grove, Anāthapiṇḍika’s monastery. Now at that time Venerable Nanda, the Buddha’s brother and maternal cousin, informed several mendicants: “I lead the spiritual life dissatisfied. I am unable to keep up the spiritual life. I shall resign the training and return to a lesser life.”