According to search-discovered classical Islamic scholarship, the prohibition of the 'rival one in Quba' refers to the historical event of Masjid al-Dirar (the Mosque of Harm). As detailed in the tafsir of Ibn Kathir and Al-Tabari on Quran 9:107-108, this structure was built by hypocrites not for sincere worship, but to cause 'harm (dirar), disbelief (kufr), and division (tafriq)' among the believers. Allah commanded Prophet Muhammad (PBUH) never to pray therein, establishing a divine principle that the legitimacy of a place of worship is determined by its foundation and intention. The verse contrasts this forbidden site with the 'mosque founded on piety (taqwa) from the first day'—identified as Masjid Quba—which is more worthy of prayer. This event provides the definitive Quranic and Prophetic ruling against establishing religious centers with the intent to undermine the unity and integrity of the Muslim community, emphasizing that sincere intention is the bedrock of all acceptable worship.