“Nicholas Humphrey, a Cambridge psychologist, was the first to see clearly the solution to this puzzle. We use our intellects not to solve practical problems, but to outwit each other. Deceiving people, detecting deceit, understanding people's motives, manipulating people -these are what the intellect is used for. So what matters is not how clever and crafty you are, but how much cleverer and craftier than other people. The value of intellect is infinite. Selection within the species is always going to be more important than selection between the species.”

"Fethullah Gulen: Powerful but reclusive Turkish cleric", 2014

Source: Five Questions Concerning the Mind (1495), pp. 203-204

Speech in Harlem https://www.washingtonpost.com/opinions/republicans-should-follow-ben-carsons-lead-on-black-lives-matter/2015/08/17/cd242572-44d7-11e5-8e7d-9c033e6745d8_story.html (August 2015).

Parliamentary Debates [Parliament of India] Pt.2 V.12-13 (1951); also quoted in Glorious Thoughts of Nehru (1964), p. 146
Context: Ultimately what we really are matters more than what other people think of us. One has to face the modern world with its good as well as its bad and it is better on the whole, I think, that we give even licence than suppress the normal flow of opinion. That is the democratic method. But having laid that down, still I would beg to say that there is a limit to the licence that one can allow, more so in times of great peril to the State.

The Stark Munro Letters (1894)
Context: The more we progress the more we tend to progress. We advance not in arithmetical but in geometrical progression. We draw compound interest on the whole capital of knowledge and virtue which has been accumulated since the dawning of time. Some eighty thousand years are supposed to have existed between paleolithic and neolithic man. Yet in all that time he only learned to grind his flint stones instead of chipping them. But within our father's lives what changes have there not been? The railway and the telegraph, chloroform and applied electricity. Ten years now go further than a thousand then, not so much on account of our finer intellects as because the light we have shows us the way to more. Primeval man stumbled along with peering eyes, and slow, uncertain footsteps. Now we walk briskly towards our unknown goal.

Chi ni hatarakeba kado ga tatsu. Jō ni saosaseba nagasareru. Iji o tōseba kyūkutsu da. Tokaku ni hito no yo wa suminikui.
草枕 Kusamakura, 1906.

As quoted in "Close-up : I'm looking for a market for wisdom. : Leo Szilard, scientist" in LIFE‎ magazine, Vol. 51, no. 9 (1 September 1961), p. 75
Variant: If you want to succeed in the world, you don't have to be much cleverer than other people. You just have to be one day earlier.