In a message to Hamas TV broadcast at the rally, Khaled Mashaal, the movement's leader in exile, warned Israel: "Our people are able to launch a third and fourth intifada until the dawn of victory arrives."
Ismail Haniya, Hamas' leader in Gaza, told the crowd: "Today, with God's help, this movement is empowered. Today this movement is ruling.
"Some reports and secret service agencies tell you that the resistance is regressing, Hamas is regressing.
"I say to those issuing these estimations, 'Come to Gaza. Come to the oppressed West Bank to see this greatness, this glory. To see the men and women of Palestine, who are committed to steadfastness and resistance.' This is God's call and it will prevail with God's help."
Ayman Mohyeldin, Al Jazeera's correspondent in Jerusalem, said that the crowd came to both support Hamas and show their discontent with the Israeli blockade of the Gaza Strip.
Mohyeldin said: "Hamas enjoys quite a lot of popularity in the Gaza Strip, particularly in its policy towards Israel.
"It is always seen as the corner of legitimate resistance for Palestinians. It still does enjoy a wide popularity for many of its social services.
"[The rally] comes at a very interesting time for both the movement and the Palestinian people at large, as we heard from Hamas' leadership today saying that they will continue their armed struggle and their resistance.
"They also made the point that they are willing to talk to their Palestinian counterparts in the Fatah movement who dominate the West Bank and the Palestinian Authority."
Mohyeldin said that a thawing of the relationship between Hamas and Fatah was suggested by the Hamas leadership at the rally, but no indication was given as to when this would start.
Hamas were elected to power in January 2006, when the party stood for the first time in parliamentary elections.
Tensions between itself and rival Fatah led it to seize control of the Gaza Strip in June this year.
In September, Israel branded the Gaza Strip a "hostile entity" and increased restrictions on supplies and movement in and out of the area.
The UN's World Health Organization has described the humanitarian situation there as "intolerable".