Two events which destroyed the religion

 Muhammad Amin al-Astarabadi writes:

“In general, the religion has been ruined twice: one time when the Prophet passed away [the event of Saqifah], peace be upon him and his progeny, and when the usuli principles were established, and also the terminologies of the ʿammah (omaris) that have been mentioned in the usuli books, and in the books of dirāyat al-ḥadīth [science of gradings] in our rulings and traditions.”

📚al-Fawaid al-Madaniyah, P368-369