The Vedanta Sutras of Badarayana, Commentary by Sankara (SBE38), tr. by George Thibaut  at sacred-texts.com
6. And the ideas of Âditya and so on (are to be superimposed) on the members (of the sacrificial action); owing to the effectuation (of the result of the sacrifice).
'He who burns up these, let a man meditate upon him as udgîtha' (Kh. Up. I, 3, i); 'Let a man meditate on the fivefold Sâman in the worlds' (Kh. Up. II, 2, i); 'Let a man meditate on the sevenfold Sâman in speech' (Kh. Up. II, 8, i); 'This earth is the Rik, fire is Sâman' (Kh. Up. I, 6, i).--With regard to these and similar meditations limited to members of sacrificial action, there arises a doubt whether the text enjoins contemplations on the udgîtha and so on superinduced on Âditya and so on, or else contemplations on Âditya, &c. superinduced on the udgîtha and so on.
No definite rule can here be established, the pûrvapakshin maintains, since there is no basis for such a rule. For in the present case we are unable to ascertain any special pre-eminence, while we were able to do so in the case of Brahman. Of Brahman, which is the cause of the whole world and free from all evil and so on, we can assert definitively that it is superior to Âditya and so on; the udgîtha and so on, on the other hand, are equally mere effects, and we cannot therefore with certainty ascribe to any of them any pre-eminence.--Or else we may decide that the ideas of the udgîtha and so on arc to be superinduced exclusively on Âditya and so on. For the udgîtha and so on are of the nature of sacrificial work, and as it is known that the fruit is attained through the work, Âditya
and so on if meditated upon as udgîtha and so on will themselves become of the nature of work and thereby be causes of fruit.--Moreover, the text, 'This earth is the Rik, the fire is the Sâman,' is followed by the complementary passage, 'this Sâman is placed upon this Rik,' where the word 'Rik' denotes the earth and the word 'Sâman' the fire. Now this (viz. this calling the earth 'Rik' and calling the fire 'Sâman') is possible only if the meaning of the passage is that the earth and the fire have to be viewed as Rik and Sâman; not if the Rik and the Sâman were to be contemplated as earth and fire. For the term 'king' is metaphorically applied to the charioteer--and not the term 'charioteer' to the king--the reason being that the charioteer may be viewed as a king.--Again in the text, 'Let a man meditate upon the fivefold Sâman in the world,.' the use of the locative case 'in the worlds' intimates that the meditation on the Sâman is to be superimposed on the worlds as its locus. This is also proved by the analogous passage, 'This Gâyatra Sâman is woven on the vital airs' (Kh. Up. II, 11, 1).--Moreover (as proved before), in passages such as 'Âditya is Brahman, this is the instruction.' Brahman, which is mentioned last, is superimposed on Âditya, which is mentioned first. In the same way the earth, &c., are mentioned first, and the hiṅkâra, &c., mentioned last in passages such as 'The earth is the hiṅkâra' (Kh. Up. II. 2, i).--For all these reasons the idea of members of sacrificial action has to be transferred to Âditya and so on, which are not such members.
To this we make the following reply. The ideas of Âditya and so on are exclusively to be transferred to members of sacrificial action, such as the udgîtha and so on. For what reason?--' On account of effectuation '--that means: Because thus, through their connexion with the supersensuous result (of the sacrificial work under discussion), when the udgîtha and so on are ceremonially qualified by being viewed as Âditya and so on, the sacrificial work is successful 1. A scriptural passage--viz. Kh. Up. I, 1.10,
[paragraph continues] 'Whatever one performs with knowledge, faith, and the Upanishad is more powerful'--moreover expressly declares that knowledge causes the success of sacrificial work.--Well then, an objection is raised, let this be admitted with regard to those meditations which have for their result the success of certain works; but how is it with meditations that have independent fruits of their own? Of this latter nature is e.g. the meditation referred to in Kh. Up. II, 2, 3, 'He who knowing this meditates on the fivefold Sâman in the worlds (to him belong the worlds in an ascending and a descending scale).'--In those cases also, we reply, the meditation falls within the sphere of a person entitled to the performance of a certain work, and therefore it is proper to assume that it has a fruit only through its connexion with the supersensuous result of the work under the heading of which it is mentioned; the case being analogous to that of the godohana-vessel 1.--And as Âditya and so on are of the nature of fruits of action, they may be viewed as superior to the udgîtha and so on which are of the nature of action only. Scriptural texts expressly teach that the reaching of Âditya (the sun) and so on constitutes the fruit of certain works.--Moreover the initial passages, 'Let a man meditate on the syllable Om as the udgîtha,' and 'Of this syllable the full account is this' (Kh. Up. I, 1, 1), represent the udgîtha only as the object of meditation, and only after that the
text enjoins the contemplations on Âditya and so on.--Nor can we accept the remark that Âditya and so on being meditated upon as udgîtha, &c., assume thereby the nature of work and thus will be productive of fruit. For pious meditation is in itself of the nature of work, and thus capable of producing a result. And if the udgîtha and so on are meditated upon as Âditya, &c., they do not therefore cease to be of the nature of work.--In the passage, 'This Sâman is placed upon this Rik,' the words 'Rik' and 'Sâman' are employed to denote the earth and Agni by means of implication (lakshanâ), and implication may be based, according to opportunity, either on a less or more remote connexion of sense. Although, therefore, the intention of the passage is to enjoin the contemplation of the Rik and the Sâman as earth and Agni, yet--as the Rik and the Sâman are mentioned separately and as the earth and Agni are mentioned close by--we decide that, on the ground of their connexion with the Rik and Sâman, the words 'Rik' and 'Sâman' are employed to denote them (i.e. earth and Agni) only. For we also cannot altogether deny that the word 'charioteer' may, for some reason or other, metaphorically denote a king.--Moreover the position of the words in the clause, 'Just this (earth) is Rik,' declares that the Rik is of the nature of earth; while if the text wanted to declare that the earth is of the nature of Rik, the words would be arranged as follows, 'this earth is just Rik'--Moreover the concluding clause. 'He who knowing this sings the Sâman,' refers only to a cognition based on a subordinate member (of sacrificial action), not to one based on the earth and so on.--Analogously in the passage, 'Let a man meditate (on) the fivefold Sâman in the worlds,' the worlds--although enounced in the locative case--have to be superimposed on the Sâman, as the circumstance of the 'Sâman' being exhibited in the objective case indicates it to be the object of meditation. For if the worlds are superimposed on the Sâman, the Sâman is meditated upon as the Self of the worlds; while in the opposite case the worlds would be meditated upon as the Self of the Sâman.--The same remark applies to the passage, 'This Gâyatra
[paragraph continues] Sâman is woven on the prânas' (Kh. Up. II, 11, 1).--Where again both members of the sentence are equally exhibited in the objective case, viz. in the passage, 'Let a man meditate on the sevenfold Sâman (as) the sun' (Kh. Up. II, 9, 1), we observe that the introductory passages--viz. 'Meditation on the whole Sâman is good;' 'Thus for the fivefold Sâman;' 'Next for the sevenfold Sâman' (Kh. Up. II, 1, 1; 7, 2; 8, 1)--represent the Sâman only as the object of meditation, and therefrom conclude that Âditya has to be superinduced on it. and not the reverse.--From this very circumstance of the Sâman being the object of meditation, it follows that even in cases where the two members of the sentence have a reverse position--such as 'The earth (is) the hiṅkâra,' &c.--the hiṅkâra, &c., have to be viewed as earth and so on; and not the reverse.--From all this it follows that reflections based on things not forming constituent members of the sacrifice, such as Âditya and so on, are to be superimposed on the udgîtha and the like which are such constituent members.
346:1 Certain constituent members of the sacrificial action--such as p. 347 the udgîtha--undergo a certain ceremonial purification (samskâra) by being meditated upon as Âditya and so on. The meditations therefore contribute, through the mediation of the constituent members, towards the apûrva, the supersensuous result of the entire sacrifice.
347:1 The sacred text promises a special fruit for the employment of the milking-pail (instead of the ordinary kamasa), viz. the obtainment of cattle; nevertheless that fruit is obtained only in so far as the godohana subserves the accomplishment of the apûrva of the sacrifice. Analogously those meditations on members of sacrificial works for which the text promises a separate fruit obtain that fruit only in so far as they effect a mysterious samskâra in those members, and thereby subserve the apûrva of the sacrifice.