In a December 18, 2021 interview with the Iranian news agency Tasnim, Hamas official Moussa Abu Marzouq said that "the Palestinian resistance today resembles a regular army, with thousands of soldiers willing to die as martyrs, who are well trained and whose morale is high." He also revealed that the development of the Gaza-made rockets began in 2001, even before the Israeli withdrawal from the Gaza Strip, and that similar experiments were also conducted in the West Bank. He praised Iran for its role in arming and developing the arsenal of the Palestinian resistance in Gaza, and supported the statement of Hizbullah Secretary-General Hassan Nasrallah regarding the possibility of uniting the fronts against Israel in the case of a war with it.
Moussa Abu Marzouq (Source: Tasnimnews.com)
The interview took place several days after Hamas' military wing, the 'Izz Al-Din Al-Qassam Brigades, held a military exercise called Shield of Jerusalem with the aim of "improving combat readiness and simulating various scenarios." The Lebanese Al-Akhbar daily reported that one of the goals of the exercise was to pressure Israel as part of the Egyptian-brokered negotiations for a possible prisoner exchange deal, and to show that the 'Izz Al-Din Al-Qassam Brigades are capable of capturing more Israeli soldiers. Footage of the exercise released by Hamas indeed shows that one of the scenarios practiced was of storming an Israeli base and capturing of an Armored Corps soldier, similar to the kidnapping of Gilad Shalit. Following the exercise, the Joint Operations Room of the Palestinian resistance factions announced that another exercise is planned soon involving the military wings of all the Gazan organizations. 
For footage of the recent exercise, click below.
The following are translated excerpts from Moussa Abu Marzouq's interview:
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Abu Marzouq: We Have Thousands Of Well-Trained And Highly Motivated Soldiers Willing To Be Martyred
Asked about Iran's contribution to Gaza's rocket arsenal and to the ability to manufacture rockets with different ranges, Moussa Abu Marzouq said: "Thank Allah, the Palestinian resistance has never lacked for munitions since the start of the popular uprising against the Jewish gangs even before the  Nakba. We fought and prepared to the best of our abilities. The resistance in Gaza now continues the Palestinian struggle that has been ongoing for decades and which is a source of pride for the Palestinian people and for the Arab and Islamic nation.
"The Palestinian resistance today resembles a regular army, with thousands of soldiers willing to die was martyrs, who are well trained and whose morale is high. In addition, the resistance started to focus on developing its arsenal based on a strategic approach. The development of the rockets began in 2001, before Israel's withdrawal from the Gaza Strip, even though other kinds of weapons were suitable for the struggle against the [Israeli] settlements that had been planted in the Strip and there was no need for rockets. However, the strategic approach to the struggle prompted the jihad fighters to develop [their abilities] and prepare for the next stage, [the one after the struggle against] the settlements in Gaza. Similar experiments were also conducted in the West Bank.
"These efforts continued, and then the jihad fighters received important assistance from Iran, who armed [us], shared its accumulated experience and technology and developed the rockets so that they could reach every part of occupied Palestine…"
Asked about the position of the Palestinian resistance on the statements of Hizbullah Secretary-General Hassan Nasrallah in June 2021 that "any violation against Jerusalem and the holy places will lead to a regional war," Abu Marzouq said: "Any war connected to the holy places is our war, and we will not let the Zionist enemy harm them. Uniting the fronts [against Israel] is a vital interest, for it will diffuse the forces of the Israeli army. We have always favored fighting the Zionist enemy as much as possible and increasing the pressure on it, and we still do…"
 T.me/qassambrigades, December 15, 2021.
 Al-Akhbar (Lebanon), December 16, 2021.
 T.me/resistFactions, December 16, 2021. For footage of a similar exercise last year, see MEMRI TV Clip No. 8574, Gaza Joint Command Military Exercise Showcases Hamas', PIJ's Commando And Missile, Drone Capabilities, December 29, 2020.
 Tasnimnews.com, December 18, 2021.
 An allusion to Quran 8:60, which is also the motto of the Muslim Brotherhood movement, with which Hamas is affiliated: "And prepare against them whatever you are able of power and of steeds of war by which you may terrify the enemy of Allah and your enemy and others besides them whom you do not know [but] whom Allah knows. And whatever you spend in the cause of Allah will be fully repaid to you, and you will not be wronged."
 Almanar.com.lb, June 8, 2021.