Skandapurana 6.3.227.27

6.3.227.27

ekāśanaṃ brahmacaryaṃ bhūśayyāṃ satyavāditām .
varjanaṃ ca parānnasya pratigrahavivarjanam .. 227.27 ..

eating once a day, celibacy, sleeping on the ground, truthfulness in speech, / abstaining from another's food, and complete avoidance of accepting gifts;