There are many things that happen in this life that we consider foolishness and not righteousness while some are righteousness and not foolishness. I want you to base your judgments on this true life story

I have a very distant cousin that once told me of a true life story that the victim of this story shared with her. She told me that there is this person close to her going to farm with her mother one fateful day, on their way to the farm they stumbled on a briefcase loaded with dollars (The amount is unknown to them). She and her mother walk past the money hoping that the owner could come back looking for it. They returned home that fateful day and heard news on the radio that a bank very close to them has been robbed earlier that morning and the thieves has gone with lots of money from the bank. So they flashed back to the briefcase, and they thought it could have been in the process of being in haste that one of the briefcases fell from the vehicle of the thieves. They didn't bother to go back to the place they saw that briefcase thinking a lucky person would have picked it up.

Some weeks later they walk through that same path they saw the briefcase loaded with dollars, lo and behold the money was still there, but as at that time the rain has seriously beaten that briefcase and the money inside has been destroyed as a result of the rain. Though they were unhappy that the money was destroyed but they did not regret not taking the money. Mind you these people are still farmers till date.

What would you term this to be? "Righteousness or foolishness"

To the world, it may appear to be foolishness
But to those who know what is right and wrong, it is 'righteousness' or rather, the right thing to do
In Christianity, a lot of things we do will appear to be 'foolish' to the world. For example, why should I turn the other cheek when someone strikes me? The average person will strike back.
Why should I love and pray for my enemies? The average person in the world will wish death for his enemies
Why should I be good to those who spitefully use me? The average person will be nice to only those who are nice to them
So, you see, a lot of things we Christians do make us appear foolish and weak, but we know what the Bible says, and we know we are actually doing what is right.

Righteousness here should me returning the money rather than leave it to be destroyed.