Śaṅkaraon Brahma Sūtra 3.3.56

Or else we may put the matter as follows. There is no reason whatever to suspect a contradiction if we declare certain vidyas enjoined in one 6"akhd to be valid for the udgitha and so on belonging to other Vakhas also ; for there is no more room for contradiction than in the case of mantras. We observe that mantras, acts, and qualities of acts which are enjoined in one JS'akha are taken over by other iakhas also. So e.g. the members of certain Ya^ur- veda ^''akhds do not exhibit in their text the mantra, ‘ Thou art the ku/aru which accompanies the taking of the stone (with which the rice-grains arc ground) ; all the same we meet in their text with the following injunction of applica- tion, ‘Thou art the cock, with this mantra he takes the stone ; or else with the mantra, Thou art the ku/aru/ [38] ^ Maitrdyawiya Sazwhitd I, i, 6. — Again, the text of some ^Sakhd does not contain a direct injunction of the five offerings called pray^^^s which are made to the fuel and so on, but it contains the injunction of secondary matters connected with the pray^l^s, viz. in the passage, ‘ the seasons indeed are the praya^as ; they are to be offered in one and the same spot Again, the text of some wS'akhd does not contain an injunction as to the species of the animal to be sacrificed to Agnishomau —such as would be ‘ a he-goat is sacrificed to Agnishomau ^ / but in the same 6’akha we meet with a mantra which contains the required specification, ^Hotr/, recite the anuvakyfi, for the fat of the omentum of the he-goat Similarly mantras enjoined in one Veda only, such as Agni, promote the hautra, promote the sacrifice/ are seen to be taken over into other Vedas also. Another example (of the transference of mantras) is supplied by the hymn, * He who as soon as born showed himself intelligent,’ &c. {Rik, Sawh. II, 1:2), which although read in the text of the Bahvr/Aas is employed in the Taittiriya Veda also, according to Taitt. Sawh. VII, 5, 5, 2, ‘ The Sa^j^'aniya hymn is to be — recited.’ Just as, therefore, the members of sacri- ficial actions on which certain vidyas rest arc valid every- where, So the vidyds themselves also which rest on those members are valid for all i'akhas and Vedas.