The short answer
Researchers have found no substantive support for the claim that Confucius said this. Quote Investigator's earliest strong match appeared in the Princeton Alumni Weekly in 1982, where a professor of philosophy named Arthur Szathmary used the saying — and explicitly credited it not to himself but to an unnamed old-timer he knew. The first known linkage to Confucius came later still: a June 1985 article in the computing trade journal Computerworld, where the journalist Glenn Rifkin printed it beneath Confucius's name.
The anachronism gives it away
Even without the paper trail, the sentence does not survive a moment's thought about the world Confucius lived in. It presupposes a labour market in which an individual chooses among careers according to personal enthusiasm. That is a modern idea, and a comfortable one; in the fifth century BC, occupation was overwhelmingly a matter of birth, obligation, and necessity. The quote is not merely unsourced — it is unthinkable in its supposed context.
Why Confucius, of all people
Confucius functions in English as a kind of generic authority for aphorisms about work, harmony, and self-improvement — the same role Einstein plays for cleverness and Gandhi for peace. Attaching his name lends an anonymous piece of career advice the weight of ancient wisdom, and almost nobody checks, because there is no obvious way to check.
Is the advice even good?
It is worth separating from its false pedigree, because as counsel it is genuinely contested. Work you love is still work; loving it does not remove the effort, and the promise that it will can leave people feeling they have failed when a beloved job turns out to be tiring. A more honest version might be that work you care about makes the effort worth spending — which is a smaller claim, and a truer one.
What this means for your English
Notice the construction: never have to work a day in your life. That pattern — never … a day in your life — is an idiomatic intensifier, not a literal statement about days. English is full of these hyperbolic frames, and using one correctly signals fluency far more than a complicated tense ever will.