“I do not wish to suggest that because we were one nation we had no differences, but it is submitted that our leading men travelled throughout India . . . They learned one another’s languages . . . they saw that India was one undivided land so made by nature. They, therefore, argued that it must be one nation. Arguing thus, they established holy places in various parts of India, and fired the people with an idea of nationality in a manner unknown in other parts of the world. Any two Indians are one as no two Englishmen are.”

Ambedkar, Pakistan or the Partition of India http://www.columbia.edu/itc/mealac/pritchett/00ambedkar/ambedkar_partition/307a.html#part_2

In His speech to the nation on the day prior to the Republic Day (in 1989), p. 181-82
Commissions and Omissions by Indian Presidents and Their Conflicts with the Prime Ministers Under the Constitution: 1977-2001

Nehru, quoted in Religion, Caste, and Politics in India by C. Jaffrelot

The Hindu, "Strengthening Indianness ", Sunday, Jan 19, 2003, Available Online http://www.hinduonnet.com/thehindu/mag/2003/01/19/stories/2003011900240300.htm
2000s

Quoted from After a Century it is time to revisit Sir Syed Ahmad Khan’s legacy https://www.myind.net/Home/viewArticle/after-a-century-it-is-time-to-revisit-sir-syed-ahmad-khans-legacy Avatans Kumar Jan 27, 2018. Also quoted in The Great Speeches of Modern India by Rudranghsu Mukherjee

1900s, The Strenuous Life: Essays and Addresses (1900), National Duties
Context: Exactly as each man, while doing first his duty to his wife and the children within his home, must yet, if he hopes to amount to much, strive mightily in the world outside his home, so our nation, while first of all seeing to its own domestic well-being, must not shrink from playing its part among the great nations without. Our duty may take many forms in the future as it has taken many forms in the past. Nor is it possible to lay down a hard-and-fast rule for all cases. We must ever face the fact of our shifting national needs, of the always-changing opportunities that present themselves. But we may be certain of one thing: whether we wish it or not, we cannot avoid hereafter having duties to do in the face of other nations. All that we can do is to settle whether we shall perform these duties well or ill.

V.T. Rajshekar: Dalit - the Black Untouchables of India, Clarity Press, Atlanta 1987, p.43. , quoted in Elst, Koenraad (1999). Update on the Aryan invasion debate https://web.archive.org/web/20100412074243/http://www.bharatvani.org/books/ait/ New Delhi: Aditya Prakashan.

Speech https://hansard.parliament.uk/commons/1947-07-10/debates/584499a6-8830-4426-be23-7215df06d57e/IndianIndependenceBill#2432 in the House of Commons (10 July 1947)
1940s

Source: We want Strong Ties with India: Sharon, 9 September 2003, http://www.rediff.com/news/2003/sep/09sharon1.htm