sarva-bhūtāni kaunteya
prakṛtiḿ yānti māmikām
kalpa-kṣaye punas tāni
kalpādau visṛjāmy aham

Translation of Bhagavad Gita 9.7

O son of Kunti, at the end of the millennium all material manifestations enter into My nature, and at the beginning of another millennium, by My potency, I create them again.

Commentary by Sri A.C. Bhaktivedanta Swami Prabhupada of Gaudiya Sampradaya:

The creation, maintenance and annihilation of this material cosmic manifestation are completely dependent on the supreme will of the Personality of Godhead. “At the end of the millennium” means at the death of Brahma. Brahma lives for one hundred years, and his one day is calculated at 4,300,000,000 of our earthly years. His night is of the same duration. His month consists of thirty such days and nights, and his year of twelve months. After one hundred such years, when Brahma dies, the devastation or annihilation takes place; this means that the energy manifested by the Supreme Lord is again wound up in Himself. Then again, when there is a need to manifest the cosmic world, it is done by His will. Bahu syam: “Although I am one, I shall become many.” This is the Vedic aphorism (Chandogya Upanishad 6.2.3). He expands Himself in this material energy, and the whole cosmic manifestation again takes place.

Commentary by Sri Vishvanatha Chakravarthi Thakur of Gaudiya Sampradaya:

“I understand that all these things which can presently be seen are situated in you, but at the time of destruction where will they go?” This verse answers.

All these things will merge into my energy called prakrti composed of the three gunas. At the end of the period of destruction, at the time of creation, (kalpa ksaye), I will again create everything in detail (visesena srjami).

Commentary by Sri Ramanuja of Sri Sampradaya:

9.7 All the mobile and immobile entities enter into My Prakrti at the end of a cycle, namely at the end of Brahma’s life in accordance with My will. This Prakrti, constituting My body, is designated by the term Tamas, as it cannot be differentiated into name and form. I again send forth the very same beings at the beginning of a cycle. Manu declares accordingly: ‘This universe became Tamas … by an act of will. He produced it out of His body’ (Manu, 1.5.8). The Srutis also declare thus: ‘He whose body is Avyakta’ (Su. U., 7); ‘The Avyakta merges into Aksara, the Aksara into Tamas’ (Ibid., 2); and also ‘There was Tamas; the intelligence was concealed by Tamas’ (Tai. Br., 1.8.9).

Commentary by Sri Sridhara Swami of Rudra Sampradaya:

Thus Lord Krishna has revealed that although He is the sustenance of all creation He remains unattached by His mysterious potency. That He is also the source of all creation and the cause of its dissolution as well by this same mysterious potency. The words kalpa ksaye means universal devastation at the end of Brahma’s lifetime. One year of Brahma equals 27 trillion, 438 billion and 400 million Earth years. Brahma lives for 100 of such years. After this long duration of time all living entities everywhere in creation are dissolved into prakriti or the material substratum. At the time of creation in the beginning of the next kalpa Lord Krishna again manifests all living entities and propels them into being.

Commentary by Sri Madhvacharya of Brahma Sampradaya:

For the purpose of imparting detailed knowledge Lord Krishna speaks of the dissolution of all beings at the end of a life of Brahma who is the architect of material creation. This is what is acknowledged by the words kalpa ksaye which means at the time of universal dissolution which occurs every 26 trillion 439 billion and 400 million years on Earth at the end of each Brahma’s life.

Commentary by Sri Keshava Kashmiri of Kumara Sampradaya:

What Lord Krishna states in this verse concerning the cyclic coming and going of all beings is clear; but He must be either an instrumental cause or a material cause of all beings and how can this be? If He is an instrumental cause then He cannot be designated as the substratum of everything in existence like a potter making pots. Yet if He is the material cause being the substratum of all existence is impossible as well because merging oneself into all the forms of material nature creates something which only can revert back to its original condition only after the destruction of that which was created. In this way it could be assumed that all beings abiding within the Supreme Lord will merge with Him and again will be created after He transforms Himself and that would mean the Supreme Lord is subject to modification and attachment. To ward off this misunderstanding Lord Krishna states all beings movable and immovable are subject to prakritam yanti mamakam meaning all beings leave their forms and enter into the material substratum which is under His complete control. This happens during the final dissolution at the end of a life of Brahma and at the dawn of the next creation the Supreme Lord manifests them again into forms. Thus all beings are produced in and from prakriti which is manifested by the potency of the brahman or spiritual substratum pervading all existence which emanates directly from the Supreme Lord. They dwell in it and are manifested and unmanifested by it. So in this way all beings eside in Him. The power and the powerful can never be divided or function separately. To exemplify the inseparable nature of the two, the power and the powerful manifestation is expressed jointly as the powerful.

So the reality is the Supreme Lord is the material cause of all living entities by His potency of prakriti which does it for Him without His ever being subject to any modification or attachment. He is also the instrumental cause as well because He is the creator of all creators. So it is clear that the Supreme Lord is the cause of all causes which includes both the material cause and the instrumental cause. The material substratum known also as primordial matter is insentient and hence cannot be separated by material nature because the modification and transformations into its subdivisions of the three gunas or modes of goodness, passion and ignorance fully depend upon it for their activity but through all the processes the potency of the Supreme Lord is influencing all to act in the way prescribed.

Therefore there is no contradiction and it can be clearly understood that the Supreme Lord through His spiritual potency known as the brahman which manifests prakriti which is the material cause of all existence where unlimited myriad of diverse and variegated forms are seen to manifest. Yet although the Supreme Lord is the ultimate source of all beings He ever remains unattached and untainted by the qualities and attributes of insentient material nature both corporeal and subtle. This is because the Supreme Lord is the sovereign ruler of all including His phenomenal spiritual potencies which are beyond the realm of human thought and intellect.

Commentary by Sri Adi Shankaracharya of Advaita Sampradaya:

9.7 Kaunteya, O son of Kunti; sarva-bhutani, all the beings-all the beings which, like wind abiding in space, abide thus in Me during their period of existence; yanti, go back; kalpa-ksaye, at the end of a cycle, at the time of dissolution; mamikam prakrtim, to My Prakrti which consists of the three gunas (qualities; see 7.13) and is (called My) lower Nature. Punah, again; aham, I; visrjami, project forth, create; tani, them, the beings, as before [As before: as in previous cycles of creation.]; kalpadau, at the beginning of a cycle, at the time of creation.

Commentary by Sri Abhinavagupta of Kaula Tantra Sampradaya:

9.7 Sarva- etc. Nature : unmanifest form.

Sanskrit Shloka Without Transliteration Marks:

sarva-bhutani kaunteya
prakrtim yanti mamikam
kalpa-ksaye punas tani
kalpadau visrjamy aham

Sanskrit to English Word for Word Meanings:

sarva-bhūtāni — all created entities; kaunteya — O son of Kuntī; prakṛtim — nature; yānti — enter; māmikām — My; kalpa-kṣaye — at the end of the millennium; punaḥ — again; tāni — all those; kalpa-ādau — in the beginning of the millennium; visṛjāmi — create; aham — I.