Adam Clarke on Jeremiah 5:1

Broad places - Market-places, and those where there was most public resort.

If ye can find a man - A certain philosopher went through the streets of Athens with a lighted lamp in his hand; and being asked what he sought, answered, "I am seeking to find a Man." So in Jerusalem none was found, on the most diligent search, who acted worthy the character of a rational being.

I will pardon it - I will spare the city for the sake of one righteous person. So at the intercession of Abraham, God would have spared Sodom if there had been ten righteous persons found in it; Gen 18:26.