“The Bhagavad-Gita is perhaps the most systematic scriptural statement of the Perennial Philosophy.”

as quoted in Londhe, S. (2008). A tribute to Hinduism: Thoughts and wisdom spanning continents and time about India and her culture https://books.google.com/books/about/A_Tribute_to_Hinduism.html?id=G3AMAQAAMAAJ

Source: Autobiography of a Yogi, Chapter 42 - "Last Days With My Guru"

I suppose we all thought that, one way or another.
Interview about the Trinity explosion, first broadcast as part of the television documentary The Decision to Drop the Bomb (1965), produced by Fred Freed, NBC White Paper; the translation is his own. online video at atomicarchive.com http://www.atomicarchive.com/Movies/Movie8.shtml
It is possible that Oppenheimer is referring to Bhagavad-Gita xi:32: श्रीभगवानुवाच | कालोऽस्मि लोकक्षयकृत्प्रवृद्धो लोकान्समाहर्तुमिह प्रवृत्त: (śrī-bhagavān uvāca kālo 'smi loka-kṣaya-kṛt pravṛddho lokān samāhartum iha pravṛttaḥ) ("The blessed one [Krishna] said: I am the full-grown [or mighty] world-destroying Time [or Death], now engaged in destroying the worlds").

The Ideal of the Karmayogin (1921), p. 9
Context: Hinduism, which is the most skeptical and the most believing of all, the most skeptical because it has questioned and experimented the most, the most believing because it has the deepest experience and the most varied and positive spiritual knowledge, that wider Hinduism which is not a dogma or combination of dogmas but a law of life, which is not a social framework but the spirit of a past and [future]] social evolution, which rejects nothing but insists on testing and experiencing everything and when tested and experienced, turning in to the soul's uses, in this Hinduism, we find the basis of future world religion. This Sanatana Dharma has many scriptures: The Veda, the Vedanta, the Gita, the Upanishads, the Darshanas, the Puranas, the Tantras, nor could it reject the Bible or the Koran, but its real, the most authoritative scripture is in the heart in which the Eternal has his dwelling.

“Western Civ,” p. 19.
Giants and Dwarfs (1990)
Context: I am now even more persuaded of the urgent need to study why Socrates was accused. The dislike of philosophy is perennial, and the seeds of the condemnation of Socrates are present at all times, not in the bosoms of pleasure-seekers, who don’t give a damn, but in those of high-minded and idealistic persons who do not want to submit their aspirations to examination.

Introduction to the Bhagavad-Gita (1944)
Context: I have tried to show that the Perennial Philosophy and its ethical corollaries constitute a Highest Common Factor, present in all the major religions of the world. To affirm this truth has never been more imperatively necessary than at the present time. There will never be enduring peace unless and until human beings come to accept a philosophy of life more adequate to the cosmic and psychological facts than the insane idolatries of nationalism and the advertising man’s apocalyptic faith in Progress towards a mechanized New Jerusalem. All the elements of this philosophy are present, as we have seen, in the traditional religions. But in existing circumstances there is not the slightest chance that any of the traditional religions will obtain universal acceptance. Europeans and Americans will see no reason for being converted to Hinduism, say, or Buddhism. And the people of Asia can hardly be expected to renounce their own traditions for the Christianity professed, often sincerely, by the imperialists who, for four hundred years and more, have been systematically attacking, exploiting, and oppressing, and are now trying to finish off the work of destruction by “educating” them. But happily there is the Highest Common Factor of all religions, the Perennial Philosophy which has always and everywhere been the metaphysical system of prophets, saints and sages. It is perfectly possible for people to remain good Christians, Hindus, Buddhists, or Moslems and yet to be united in full agreement on the basic doctrines of the Perennial Philosophy.

Remarkable Quotes
Source: As quoted in “Don Pañong – Genius" by A.V.H. Hartendorp in Philippine Magazine (September 1929), p. 211.

Anecdote reported by Dr. Robert Smith, late Master of Trinity College, to his student Richard Watson, as something that Newton expressed when he was writing his Commentary On Daniel. In Watson's Apology for the Bible. London 8vo. (1806), p. 57

After having read a French translation of the Bhagavad Gita given to her by an Indian who had “advised her to envisage Krishna as the immanent Godhead, as the Divine within ourselves, quoted in "Paris (1897-1904)", and in II. PARIS (1897-1904), Sri Aurobindo's Ashram http://www.motherandsriaurobindo.org/Content.aspx?ContentURL=_staticcontent/sriaurobindoashram/-04%20centers/india/pondicherry/sri%20aurobindo%20society/wilfried/The%20Mother%20-%20A%20Short%20Biography/-005_Paris%20(1897-1904).htm.