I was with Ali ibn Musa Ar-Ridha’ (a.s.) when he was leaving Neishaboor. He was riding in a carriage pulled by a grayish mule. Then Muhammad ibn Rafe’a, Ahmad ibn al-Harith, Yahya ibn Yahya, Ishaq ibn Rahovayeh and some of the scholars grabbed the mule’s harness at Marba’at and said, ‘By your forefathers, the Pure! Please narrate a tradition for us from your father.’ Then he brought his head out of the carriage.He was wearing a double-sided fur cloak. He (a.s.) said, ‘My father Musa ibn Ja’far (a.s.) - the good-doing servant -narrated that his father Ja’far ibn Muhammad As-Sadiq (a.s.) quoted on the authority of his father Abu Ja’far Muhammad ibn Ali (a.s.) - the analyzer of the Knowledge of the Prophets - on the authority of his father Ali ibn Al-Husayn (a.s.) - the Master of the Worshippers - on the authority of his father Al-Husayn (a.s.) - the Master of Youth in Paradise - on the authority of his father Ali ibn Abi Talib (a.s.), on the authority of God’s Prophet (S) that he had heard Gabriel say that God - the Exalted the Magnificent - say, “I am God. There is no god but Me. Worship Me then. Whoever of you sincerely witnesses to “there is no god but God” can enter My Stronghold. And whoever enters My Stronghold is secure from My punishment.”