“We strive toward a goal, and whether we achieve it or not is important, but it's not what's most important. What matters is how we move toward that goal.”

Original from Zig Ziglar https://en.wikiquote.org/wiki/Zig_Ziglar
Misattributed

As quoted in Secrets of Superstar Speakers: Wisdom from the Greatest Motivators of Our Time (2000) by Lilly Walters, p. 96
Variant: What you get by achieving your goals is not as important as what you become by achieving your goals.

Attributed to Zig Ziglar
Misattributed

Darwin's Dangerous Disciple: An Interview by Frank Miele (1995)

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.

Horvendile, in The High Place : A Comedy of Disenchantment (1923), Ch. XVI: Some Victims of Flamberge.

Source: Secrets of the Millionaire Mind: Mastering the Inner Game of Wealth

Part 6 "Beyond System — The Ultimate Source of Jeet Kune Do"
Jeet Kune Do (1997)