"Al-Aqsa mosque will not be liberated by negotiations but in a final battle. Allah has promised his people this victory," Mahmoud al-Zahar told about 100 Hamas supporters in the southern Gaza city of Khan Yunis on Thursday.
Speaking against the backdrop of a poster of nine human bombers who hailed from Khan Yunis, al-Zahar also derided the Palestinian interior ministry's call on Tuesday for all Palestinian groups to disarm.
"People in the interior ministry say that in two weeks, after the Zionist withdraw, they will disarm the factions.
"Hamas suffered a lot and many people were killed. After the victory is achieved how can some people say 'you didn't do anything and you must disarm'. This is not fair, this is why we will keep our weapons."
He warned Israel's withdrawal was no guarantee that it would not strike the Gaza Strip or reoccupy the crowded Mediterranean coastal strip.
"We cannot believe they will withdraw and not come back. Because of this, we say the resistance can not stop."
Al-Zahar also turned his fire on the PLO, the umbrella organisation for all Palestinian factions, which the Islamic party has always refused to join.
"After Oslo, the PLO became weaker. The extent of the PLO's weakness became clear after (Bill) Clinton visited the Gaza Strip (in 1998). Then it was definite that we needed a new agreement and principles among the Palestinian people," al-Zahar said.
"Now the PLO is only a name and has its embassies. It has lost its popularity with the Palestinian people."