Shatapatha Brahmana 5.4.5.17

5.4.5.17

tadu tathā na kuryāt | hvalati vā eṣa yo yajñapathādetyeti vā eṣa yajñapathādya upasatpathādeti tasmādupasatpathādeva neyāt

But let him not do it in this way; for he who departs from the path of the sacrifice stumbles, and he who departs from the path of the Upasads certainly departs from the path of the sacrifice: let him therefore not depart from the path of the Upasads.