Religion is a mighty motive force. So is rapine. But where religion in goaded on by rapine and rapine serves as a handmaid to religion, the propelling force that is generated by these together is only equalled by the profundity of human misery and devastation they leave behind them in their march. Heaven and Hell making a common case - such were the forces, overwhelmingly furious, that took India by surprise the day that Mahmud Ghaznavi crossed the Indus and invaded her.