Iron till it be thoroughly heated is incapable to be wrought; so God sees good to cast some men into the furnace of affliction, and then beats them on his anvil into what frame he pleases. ↗
The Jewish background is not that far from the black groove. Blacks are downtrodden, Jews are downtrodden, therefore they have something in common in that affliction. Being downtrodden often makes one more empathetic and sympathetic. ↗