What is the ruling on praying in the mosques of a Muslim sect that has transgressed and spread corruption on earth, and has permitted the shedding of Muslim blood, knowing that we maintain our prayers in our homes?

Congregational prayer is obligatory for adult men, and the mosque is not a condition for its obligation. However, the virtue of attending the mosque is missed without a valid excuse. One should attend congregational prayers in mosques even if those in charge are people of innovation, as long as it does not lead them to disbelief. Sheikh al-Islam Ibn Taymiyyah said: "If the congregant knows that the imam is an innovator who calls to his innovation, or an openly sinful person, and he is the regular imam behind whom prayer is only possible... then the congregant prays behind him according to the general consensus of the Salaf and later generations." So, praying in congregation is better than a man praying alone, even if the imam is sinful, and this is the view of the majority of scholars. Abandoning Friday prayers and congregational prayers behind a wicked imam is considered an innovation by Imam Ahmad and other imams of the Sunnah. The correct view is that prayer behind them is valid and does not need to be repeated, as the Companions prayed behind wicked imams. If abandoning the sinful or innovative imam leads to his repentance or removal, without depriving the congregant of Friday and congregational prayers, then that is good. However, if it results in missing congregational prayer, then only an innovator would abandon praying behind them. If the ruling imams are not disbelievers, there is no meaning in disrupting congregational prayer and abandoning mosques.