A question regarding one who prayed behind the Shi'ah in their mosque

Question:
I traveled to al-Ahsa last year, and when it was time for the Maghrib prayer, I entered the mosque to pray. I prayed with them and finished the prayer, and then they stood up for the 'Isha' prayer. I had prayed with them because I did not know anything about them. When I came out of the mosque and asked, they told me that their school of jurisprudence is the Shi'ah. Will I be held accountable for a sin or not? Please inform me, may Allah reward you.

Answer:
You must repeat the 'Isha' prayer because you prayed it before its time, so you have to repeat it. Do not go back to praying with them, because there is a major defect in their creed. The Shi'ah are generally characterized by exaggeration regarding the People of the House (Ahl al-Bayt). They are divided into many sections and sects, but this 'Isha' prayer that you prayed with them, you must repeat it because you prayed it before its time. It is their custom to combine the Zuhr and 'Asr prayers, and the Maghrib and 'Isha' prayers, except for those among them whom Allah wills.