ভূমিকা
Shiavault - a Vault of Shia Islamic Books Anecdotes From the Lives of the 14 Ma’sumeen Imam Ali Ar-ridha (a) Once when our 8th Imam, Imam Ali ar-Ridha (A) was travelling through a town called Nishapur, the people of the town asked Imam (A) to tell them a hadith from the Prophet (S).
Imam Ali ar-Ridha (A) told them the following hadith: "My father Musa al-Kadhim (A) told me, from his father Ja'far as-Sadiq (A), from his father Muhammad al-Baqir (A), from his father Ali Zainul Abideen (A), from his father the martyr of Kerbala (Husain) (A), from his father Ali ibn Abu Talib (A), from the Holy Prophet (S).
from Jibrail, from Allah: "The Kalima of La ilaha illallah is My fort, and whosoever says it will enter My fort, and whosoever enters My fort is safe from My punishment." This hadith is known as the golden chain hadith. This is because each member of the chain was a Ma'sum. The people of Nishapur began reciting the Kalima. Imam Ali ar-Ridha (A) continued, that there was one condition to the safety in this fort and that was that they had to obey and follow the Imams (A).
Moral: Just to say something will be of no use. Only when you understand what you are saying and believe in it enough to follow it then will it be of use to you. The king at the time of our 7th Imam, Imam Ali ar-Ridha (A) was Ma'mun. Ma'mun had forced Imam (A) to take the position of his heir apparent (i.e. Imam (A) was supposed to take over as king after Ma'mun); because he wanted to be accepted by the Shias.
Although Imam (A) did not want to take this position, he made full use of it to preach Islam openly. To show to the people how much he thought of Imam (A), Ma'mun changed the colour of his court from black to green (the colour of the Imams (A).), he also had new coins made with Imam Ali ar-Ridha's (A) name on it. Each Imam (A) is remembered for a specific thing: eg.4th Imam, Imam Zainul Abideen (A) - In illness. 6th Imam, Imam Ja'far as-Sadiq (A) - For sustenance.
And in the same way our 8th Imam, Imam Ali ar-Ridha (A) is called upon when someone is about to go on a journey. When you go on journeys you take with you something called Imam-e-Zaamin (another name for Imam Ali ar-Ridha (A)) which is some money tied in a cloth. This tradition probably came from the time of Imam Ali ar-Ridha (A) when people used to carry money with them especially because it had Imam's (A) name on it.