What was the purpose of the ghazu in the years before Islam?

Defending the rights of Muslims to live safely and do their religious practice freely like in Badr Ghazua; Muslims were tortured and exiled from their homes only because they fellow a new religion that has equaled the masters and the slaves in the rights and duties, in the eyes of the Islamic community and Allah( the god).

Another Example: in Oohod Ghazua Muslims enemies attacked Muslim s to take revenge of their loss in Badr Ghazua.

The answer is william henry harrison pursued and defeated british forces retreating into canada.