Śatapatha Brāhmaṇa ("of a hundred paths") 1.1.2.7

1.1.2.7

yajño vasanti na kauṣṭasya na kumbhyai bhastrāyai ha smarṣayo gṛhṇanti tadvṛṣīnprati bhastrāyai yajūṃṣyāsustānyetarhi prākṛtāni yajñādyajñaṃ nirmimā iti tasmādanasa evagṛhṇīyāt

The cart further is (one of the means of) the sacrifice; for the cart is indeed (one of the means of) sacrifice. To the cart, therefore, refer the (following) Yagus-texts, and not to a store-room, nor to a jar. The Rishis, it is true, once took (the rice) from a leathern bag, and hence, in the case of the Rishis, the Yagus-texts applied to a leathern bag. Here, however, they are taken in their natural application. Because he thinks 'from (or, by means of) the sacrifice I will perform the sacrifice,' let him, therefore, take (rice) from the cart.