Śatapatha Brāhmaṇa ("of a hundred paths") 3.3.4.19

3.3.4.19

kauśika brāhmaṇa gautama bruvāṇeti | śaśvaddhaitadāruṇinādhunopajñātaṃ yadgautama bruvāṇeti sa yadi kāmayeta brūyādetadyadyu kāmayetāpi nādriyetetyahe sutyāmiti yāvadahe sutyā bhavati

'O Kausika, Brahman, thou who callest thee Gautama.' Just so has this (formula) been devised in these days by Âruni, to wit, 'thou who callest thee Gautama:' he may say it, if he choose, and if he does not choose, he need not attend to it. 'In so and so many days, to the Soma-feast,' (stating) in how many days from hence the pressing is to be.