The verse that Nasrallah referenced in his Thursday speech came from Surah Al-Hajj, verse 39, and can be translated as "Permission [to fight back] is granted to those being fought, for they have been wronged. And Allah is able to help them achieve victory."
I’ve seen in commentaries that this is the first verse given to Muhammad in the context of warfare, and it was revealed to him when he left Mecca for Medina.
Until that point, Muslims were prohibited from fighting the disbelievers, but once this verse was revealed, they were permitted to engage in combat, not as aggressors, but as those "defending themselves."
Symbolism of red
It’s likely that the red background appearing behind Nasrallah during his speech symbolized revenge as well, similar to the red flag of Hussein in Shia Islam.
Exploitation of Quranic verses is a recurring part of the propaganda used by Islamist movements, both Shia and Sunni, which can provide a glimpse into the underlying tone and context which they try to convey.
For instance, while introducing the hostage-for-terrorist agreement between Israel and Hamas in November 2023, then leader of Hamas, Ismail Haniyeh, invoked a verse which, according to exegesis, refers to the historic al-Hudaybiya ceasefire treaty signed between Mohammad and the adversaries of his kin in Mecca, which lasted for several years until his forces rearmed and concluded the conquest of Mecca.
Here, too, for a Muslim inversed in the historiographic accounts of Islamic history, these verses can help associate the ceasefire agreement with one that was necessary to “complete the mission” or defeat the enemy.
A third example of Islamic references can be found in the logo of Hamas’s massacre dubbed “The Flood of Al-Aqsa.” The verse reads: “Enter unto them through the gate. If you do, you will certainly prevail,” which in turn refers to the Twelve Spies's affairs, in which the Israelites were discouraged from going into the promised land, fearing the giants who roamed the area; while two God-fearing men urged the Israelites to enter the land through the gates and trust Allah.
Figuratively, the usage of this passage by Hamas “reverses” the traditional roles, addressing the Hamas militants as if they are the modern embodiment of ancient Israelites – urging them to enter their promised land – currently roamed by the ‘giant’ Jews.
In other words, the verse chosen for the symbols of Hamas’s attack, in which they indeed entered the land through the gates of the Kibbutzim and other communities, deems the land a promised one to Palestinians or Hamas – echoing a “heavenly promise” for Hamas to conquer the land.
A Muslim who is familiar with the historiographical background of these verses surely understands the meaning of those invoked by the leaders of these organizations in an associative way, and it is incumbent upon anyone who faces them to attempt to understand these cues as well.