Imam al-Sadiq (AS) narrated, 'When Ali b. al-Husayn [i.e. Imam Zayn al-Abidin] (AS) used to go down in prostration, he would not raise his head up again until he was dripping with sweat.
Al-Kāfi #1111“Abu ‘Abd Allah (a.s.), has said that when Ali ibn al-Husayn (a.s.), would stand up for Salah (prayer), the color of his face change and in...