“To secure ourselves against defeat lies in our own hands, but the opportunity of defeating the enemy is provided by the enemy himself.”–The Art of War
Another way of putting it is, “Luck is what happens when preparation meets opportunity.”
Take a recent, international-scale example: The torture and murder of Jamal Khashoggi in the Saudi consulate in Instanbul.
The Turks were prepared, they had either bugged the consulate for audio and video, or more likely, had an inside source there, who passed a recording of the torture to them. You see, treatments like the one Jamal Khashoggi got—torture, dismemberment, decapitation—are routinely recorded, to be later shown to other potential troublemakers for the purpose of instilling in them a healthy respect for government authority. So when the Saudis did their thing rather indiscreetly (in the consulate, by 15 known government goons who all showed up at the same time in the consulate….), the Turks got the recording. Now—in exchange for not publishing the recording—the Turks are in a position to extract concessions from Saudis and from any government wanting to do business with Saudis. See how good preparation met an opportunity?
Can you think of a personal-scale example of the above principle?