The Vedanta Sutras, commentary by Sankaracharya (SBE34), tr. by George Thibaut  at sacred-texts.com
2. (Brahman is that) from which the origin, &c. (i.e. the origin, subsistence, and dissolution) of this (world proceed).
The term, &c. implies subsistence and re-absorption. That the origin is mentioned first (of the three) depends on the declaration of Scripture as well as on the natural development of a substance. Scripture declares the order
of succession of origin, subsistence, and dissolution in the passage, Taitt. Up. III, I, 'From whence these beings are born,' &c. And with regard to the second reason stated, it is known that a substrate of qualities can subsist and be dissolved only after it has entered, through origination, on the state of existence. The words 'of this' denote that substrate of qualities which is presented to us by perception and the other means of right knowledge; the genitive case indicates it to be connected with origin, &c. The words 'from which' denote the cause. The full sense of the Sûtra therefore is: That omniscient omnipotent cause from which proceed the origin, subsistence, and dissolution of this world--which world is differentiated by names and forms, contains many agents and enjoyers, is the abode of the fruits of actions, these fruits having their definite places, times, and causes 1, and the nature of whose arrangement cannot even be conceived by the mind,--that cause, we say, is Brahman. Since the other forms of existence (such as increase, decline, &c.) are included in origination, subsistence, and dissolution, only the three latter are referred to in the Sûtra. As the six stages of existence enumerated by Yâska 2 are possible only during the period of the world's subsistence, it might--were they referred to in the Sûtra--be suspected that what is meant are not the origin, subsistence, and dissolution (of the world) as dependent on the first cause. To preclude this suspicion the Sûtra is to be taken as referring, in addition to the world's origination from Brahman, only to its subsistence in Brahman, and final dissolution into Brahman.
The origin, &c. of a world possessing the attributes stated above cannot possibly proceed from anything else but a Lord possessing the stated qualities; not either from a non-intelligent prâdhana 3, or from atoms, or from non-being,
or from a being subject to transmigration 1; nor, again, can it proceed from its own nature (i.e. spontaneously, without a cause), since we observe that (for the production of effects) special places, times, and causes have invariably to be employed.
(Some of) those who maintain a Lord to be the cause of the world 2, think that the existence of a Lord different from mere transmigrating beings can be inferred by means of the argument stated just now (without recourse being had to Scripture at all).--But, it might be said, you yourself in the Sûtra under discussion have merely brought forward the same argument!--By no means, we reply. The Sûtras (i.e. literally 'the strings') have merely the purpose of stringing together the flowers of the Vedânta-passages. In reality the Vedânta-passages referred to by the Sûtras are discussed here. For the comprehension of Brahman is effected by the ascertainment, consequent on discussion, of the sense of the Vedânta-texts, not either by inference or by the other means of right knowledge. While, however, the Vedânta-passages primarily declare the cause of the origin, &c., of the world, inference also, being an instrument of right knowledge in so far as it does not contradict the Vedânta-texts, is not to be excluded as a means of confirming the meaning ascertained. Scripture itself, moreover, allows argumentation; for the passages, Bri. Up. II, 4, 5 ('the Self is to be heard, to be considered'), and Kh. Up. VI, 14, 2 ('as the man, &c., having been informed, and being able to judge for himself, would arrive at Gandhâra, in the same way a man who meets with a teacher obtains knowledge'), declare that human understanding assists Scripture 3.
Scriptural text, &c. 4, are not, in the enquiry into Brahman,
the only means of knowledge, as they are in the enquiry into active duty (i.e. in the Pûrva Mimâmsâ), but scriptural texts on the one hand, and intuition 1, &c., on the other hand, are to be had recourse to according to the occasion: firstly, because intuition is the final result of the enquiry into Brahman; secondly, because the object of the enquiry is an existing (accomplished) substance. If the object of the knowledge of Brahman were something to be accomplished, there would be no reference to intuition, and text, &c., would be the only means of knowledge. The origination of something to be accomplished depends, moreover, on man since any action either of ordinary life, or dependent on the Veda may either be done or not be done, or be done in a different way. A man, for instance, may move on either by means of a horse, or by means of his feet, or by some other means, or not at all. And again (to quote examples of actions dependent on the Veda), we meet in Scripture with sentences such as the following: 'At the atirâtra he takes the shodasin cup,' and 'at the atirâtra he does not take the shodasin cup;' or, 'he makes the oblation after the sun has risen,' and, 'he makes the oblation when the sun has not yet risen.' Just as in the quoted instances, injunctions and prohibitions, allowances of optional procedure, general rules and exceptions have their place, so they would have their place with regard to Brahman also (if the latter were a thing to be accomplished). But the fact is that no option is possible as to whether a substance is to be thus or thus, is to be or not to be. All option depends on the notions of man; but the knowledge of the real nature of a thing does not depend on the notions of man, but only on the thing itself. For to think with regard to a post, 'this is a post or a man, or something else,' is not knowledge of truth; the two ideas, 'it is a man or something else,' being false, and only the third idea, 'it
is a post,' which depends on the thing itself, falling under the head of true knowledge. Thus true knowledge of all existing things depends on the things themselves, and hence the knowledge of Brahman also depends altogether on the thing, i.e. Brahman itself.--But, it might be said, as Brahman is an existing substance, it will be the object of the other means of right knowledge also, and from this it follows that a discussion of the Vedânta-texts is purposeless.--This we deny; for as Brahman is not an object of the senses, it has no connection with those other means of knowledge. For the senses have, according to their nature, only external things for their objects, not Brahman. If Brahman were an object of the senses, we might perceive that the world is connected with Brahman as its effect; but as the effect only (i.e. the world) is perceived, it is impossible to decide (through perception) whether it is connected with Brahman or something else. Therefore the Sûtra under discussion is not meant to propound inference (as the means of knowing Brahman), but rather to set forth a Vedânta-text.--Which, then, is the Vedânta-text which the Sûtra points at as having to be considered with reference to the characteristics of Brahman?--It is the passage Taitt. Up. III, 1, 'Bhrigu Vâruni went to his father Varuna, saying, Sir, teach me Brahman,' &c., up to 'That from whence these beings are born, that by which, when born, they live, that into which they enter at their death, try to know that. That is Brahman.' The sentence finally determining the sense of this passage is found III, 6: 'From bliss these beings are born; by bliss, when born, they, live; into bliss they enter at their death.' Other passages also are to be adduced which declare the cause to be the almighty Being, whose essential nature is eternal purity, intelligence, and freedom.
That Brahman is omniscient we have been made to infer from it being shown that it is the cause of the world. To confirm this conclusion, the Sûtrakâra continues as follows:
16:1 So the compound is to be divided according to Ân. Gi. and Go.; the Bhâ. proposes another less plausible division.
16:2 According to Nirukta I, 2 the six bhâvavikârâh are: origination, existence, modification, increase, decrease, destruction.
16:3 The pradhâna, called also prakriti, is the primal causal matter of the world in the Sânkhya-system. It will be fully discussed in p. 17 later parts of this work. To avoid ambiguities, the term pradhâna has been left untranslated. Cp. Sânkhya Kârikâ 3.
17:1 Kekit tu hiranyagarbham samsârinam evâgamâg gagaddhetum âkakshate. Ânanada Giri.
17:2 Viz. the Vaiseshikas.
17:3 Âtmanah sruter ity arthah. Ânanda Giri.
17:4 Text (or direct statement), suggestive power (linga), syntactical p. 18 connection (vâkya), &c., being the means of proof made use of in the Pûrva Mîmâmsâ.
18:1 The so-called sâkshâtkâra of Brahman. The &c. comprises inference and so on.