Life’s race well run,
Life’s work well done,
Life’s crown well won,
Now comes rest.

Edward H. Parker (1823-1896) American physician, poet

Epitaph of President James Garfield (1881)
    (Source)

The phrase was engraved on a tablet placed at the head of his coffin while he lay in state at Cleveland's Memorial Park.

The passage was selected by a committee without a clear source of the material, but it appears to be a loose transcription of the first stanza of a poem Parker wrote for his mother-in-law's funeral:

Life's race well run,
Life's work all done,
Life's victory won,
Now cometh rest.

The differences may be because the Garfield epitaph was back-translated from a Latin translation of Parker's original.

Much more discussion here.