The prophet of Islam says that "If a Muslim heard the groan of an oppressed, and doesn't care, he is not a Muslim" he or she is no longer Muslim. That is why the Muslims take part in the Quds Rally to support the oppressed people of occupied Palestine obeying the Prophet Muhammad (P)'s commandments.
Quds International Day, as a brainchild of Imam Khomeini, is an annual event, held on the last Friday of Ramadan, in which the people express support for the oppressed Palestinians whose ancestral lands are occupied by the Zionist Regime. It is a double oppression on the poor Palestinians; because, Israel is not founded in Germany or any other European countries, where the alleged massacre of some Jews had taken place under Nazi rule, rather, it has been established in the occupied Palestine whose people had no role in the events. It is also injustice to displace the entire nation of Palestine from their ancestral homes by replacing the Illegal migrated European Jews in their homeland. Hence, the Muslims as well as all the freedom loving people, across the globe, participate in the assembly (parade) of Quds day to reach their innocently scream to all around the world supporting the oppressed Muslims and non-Muslims in palastine. Because, the Prophet (P) says that "If a Muslim heard the groan of an oppressed, and doesn't care, he is not a Muslim" [Kafi, v2, p164. «مَنْ سَمِعَ رَجُلا يُنَادِي يَا لَلْمُسْلِمِينَ فَلَمْ يُجِبْهُ فَلَيْسَ بِمُسْلِمٍ» ]