The lesson from history? Humans are incapable of managing their own affairs. Left to our own devices, "no flesh would be saved alive" (Matt 24:22).

When the fruits of our efforts look the most bleak, "know that He is near".

Immediately after the tribulation of those days:

‘The sun will be darkened,
     and the moon will not give its light;
the stars will fall from the sky,
     and the powers of the heavens will be shaken.’
[Matthew quoting Isaiah 13:10 here]

At that time the sign of the Son of Man will appear in heaven, and all the tribes of the earth will mourn. They will see the Son of Man coming on the clouds of heaven, with power and great glory

Matt 24:29-30