Sir Winston Churchill "cameth" when his country needed him most, as did Abraham Lincoln, George Washington - the right men for the jobs, and the times. With hindsight, throughout history many such men and women can be identified as popping up at exactly the right time, with exactly the right combination of talent and character.
My 2009 meanderings on the source of the phrase "cometh the hour, cometh the man" led me to find that the source of the exact phrase is yet to be discovered. The early 19th century writings of Sir Walter Scott contain a near match - in the novel Guy Mannering these words appear: "Because the Hour's come, and the Man" in the first edition, and in the magnum opus edition that Scott supervised in his last years, the phrase is emphasized by putting it in italics. A similar phrase appears in another of Scott's novels. Guy Mannering, by the way was an astrologer. The secondary title of Scott's novel was The Astrologer.
Later novelists and writers picked up the idea - for example:
Harriet Martineau wrote The Hour and the Man: An Historical Romance (1839), a three-volume novel about the Haitian slave leader Toussaint L'Ouverture, who contributed to the island nation's gaining independence in 1804.
American William Yancey said about Jefferson Davis, President-elect of the Confederacy in 1861: "The man and the hour have met".
In P.G. Wodehouse's Aunts Aren't Gentlemen: "And the hour ... produced the man."
Having given some more thought to the phrase's original source, I now suspect there is none - at least not of the phrase in its current form. I think biblical references must have been the original source of the idea behind the phrase.
King James Bible
Then they sought to take him: but no man laid hands on him, because his hour was not yet come.
Be ye therefore ready also: for the Son of man cometh at an hour when ye think not.
But the hour is coming, and now is...
So, though there's no evidence who was first to combine the idea of a man and "his hour", it'd be a good bet that whoever first did so was strongly influenced by biblical style, and especially by the mention of a Saviour and a "fated" hour.