“The real explanation of this failure of Hindu-Muslim unity lies in the failure to realize that what stands between the Hindus and Muslims is not a mere matter of difference, and that this antagonism is not to be attributed to material causes. It is formed by causes which take their origin in historical, religious, cultural and social antipathy, of which political antipathy is only a reflection. These form one deep river of discontent which, being regularly fed by these sources, keeps on mounting to a head and overflowing its ordinary channels. Any current of water flowing from another source, however pure, when it joins it, instead of altering the colour or diluting its strength becomes lost in the main stream. The silt of this antagonism which this current has deposited, has become permanent and deep.”

Source: This Law of Ours and Other Essays (1987), Chapter: Islam And The Spirit Of Our Times, p 133

Presidential Address to All India Muslim League's Session on March 22, 1940
Context: It is extremely difficult to appreciate why our Hindu friends fail to understand the real nature of Islam and Hinduism. They are not religions in the strict sense of the word, but are, in fact, different and distinct social orders, and it is a dream that the Hindus and Muslims can ever evolve a common nationality, and this misconception of one Indian nation has troubles and will lead India to destruction if we fail to revise our notions in time. The Hindus and Muslims belong to two different religious philosophies, social customs, litterateurs. They neither intermarry nor interdine together and, indeed, they belong to two different civilizations which are based mainly on conflicting ideas and conceptions. Their aspect on life and of life are different. It is quite clear that Hindus and Mussalmans (Muslims) derive their inspiration from different sources of history. They have different epics, different heroes, and different episodes. Very often the hero of one is a foe of the other and, likewise, their victories and defeats overlap. To yoke together two such nations under a single state, one as a numerical minority and the other as a majority, must lead to growing discontent and final destruction of any fabric that may be so built for the government of such a state.

Address to the Constituent Assembly (1947)

2000s, Who is a Hindu, (2001)

Statement of 1925, as quoted in Lord Reading (1967) by H. Montgomery Hyde, p. 387.

Source: Myths of Composite Culture and Equality of Religions (1990), p. 24

Source: Return to Roots (2002), p. 105

While this is often attributed to Nehru, it was actually something said by the Hindu Mahasabha leader, N. B. Khare.
Khare states, "Nehru’s is a very complex personality. As he himself has explained in his Autobiography, he is English by education, Muslim by culture and Hindu by an accident of birth."
"The Angry Aristocrat", N. B. Khare in A Study of Nehru, Rafiq Zakaria (ed.), 1960.
No such passage exists in Nehru's autobiography. https://www.altnews.in/did-jawaharlal-nehru-ever-say-i-am-english-by-education-muslim-by-culture-and-hindu-by-accident/
Misattributed

Presidential Address to All India Muslim League's Session on March 22, 1940
Context: It is extremely difficult to appreciate why our Hindu friends fail to understand the real nature of Islam and Hinduism. They are not religions in the strict sense of the word, but are, in fact, different and distinct social orders, and it is a dream that the Hindus and Muslims can ever evolve a common nationality, and this misconception of one Indian nation has troubles and will lead India to destruction if we fail to revise our notions in time. The Hindus and Muslims belong to two different religious philosophies, social customs, litterateurs. They neither intermarry nor interdine together and, indeed, they belong to two different civilizations which are based mainly on conflicting ideas and conceptions. Their aspect on life and of life are different. It is quite clear that Hindus and Mussalmans (Muslims) derive their inspiration from different sources of history. They have different epics, different heroes, and different episodes. Very often the hero of one is a foe of the other and, likewise, their victories and defeats overlap. To yoke together two such nations under a single state, one as a numerical minority and the other as a majority, must lead to growing discontent and final destruction of any fabric that may be so built for the government of such a state.