Proverbs 13:8 (ESV)

8 The ransom of a man’s life is his wealth, but a poor man hears no threat.

The life of a man who possesses much wealth can be subject to danger.  Because of his riches he may be taken captive and held to ransom by his captors. However, his wealth will enable him to gain his release from his captives because he has the money to buy his freedom from those who have taken him hostage. Because the poor man does not have much wealth, there is little incentive for people to hold him to ransom and so does not need to worry about threats upon his life. He has little money therefore his life is not in danger of being held to ransom.