Muhammad ibn al-Hasan al-Saffar, from Ahmad ibn Muhammad and Abdullah ibn Muhammad, from Ali ibn Mahziyar, who said: Abu Ja’far عليه السلام, peace be upon him, wrote to him (Ibn Muhammad), and I (Ali ibn Mahziyar) myself read his letter to him (Ibn Muhammad) on the road to Makkah. Imam al-Jawad عليه السلام said: "What I have made obligatory in this year of mine, and this is only the year 220, is due to a particular reason. I dislike explaining the whole reason, out of fear that it may become widely spread, but I shall explain some of it to you, if Allah سبحانه وتعالى the Exalted wills. Indeed, my followers, I ask Allah سبحانه وتعالى for their rectification or some of them, fell short regarding what was obligatory upon them, and that became known to me. So I wished to purify and cleanse them through what I did in this year of mine concerning the matter of khums. Allah سبحانه وتعالى the Exalted said, ‘Take from their wealth (O Prophet صلى الله عليه وعلى آله وسلم) charity to purify and bless them, and pray for them, surely your prayer is a source of comfort for them. And Allah سبحانه وتعالى is All-Hearing, All-Knowing. Do they not know that Allah سبحانه وتعالى alone accepts the repentance of His سبحانه وتعالى servants and receives (their) charity, and that Allah سبحانه وتعالى alone is the Accepter of Repentance, Most Merciful? Tell (them, O Prophet صلى الله عليه وعلى آله وسلم), “Do as you will. Your deeds will be observed by Allah سبحانه وتعالى, His Messenger صلى الله عليه وعلى آله وسلم, and the believers. And you will be returned to the Knower سبحانه وتعالى of the seen and unseen, then He سبحانه وتعالى will inform you of what you used to do.'” (Surah At-Tawbah 9:103-105) I did not make that obligatory upon them every year, nor do I make obligatory upon them anything except the zakat which Allah سبحانه وتعالى has made obligatory upon them. Rather, I only made khums obligatory upon them in this year of mine on gold and silver after a full year had passed over them. I did not make it obligatory upon them on goods, vessels, riding animals, servants, profit earned through trade, or landed estates, except for the estate whose matter I shall explain to you. This is as a relief from me for my followers, and as a favor from me upon them, because of what the ruler seizes from their wealth and because of what befalls them personally. As for spoils and gains, they are obligatory upon them every year. Allah سبحانه وتعالى the Exalted said, ‘Know that whatever spoils you take, one-fifth is for almighty Allah سبحانه وتعالى and the Messenger صلى الله عليه وعلى آله وسلم, his close relatives, orphans, the poor, and (needy) travellers, if you (truly) believe in Allah سبحانه وتعالى and what We سبحانه وتعالى revealed to Our servant on that decisive day when the two armies met (at Badr). And Allah سبحانه وتعالى is Most Capable of everything.’ (Surah Al-Anfal 8:41) And the gains and the benefits, may Allah سبحانه وتعالى have mercy on you, include the profit a person earns, the benefit he obtains, a valuable gift given from one person to another, an unexpected inheritance from someone other than a father or a son, wealth taken from an enemy who is destroyed, wealth whose owner is unknown, and things of the kind that reached some of my followers from the wealth of the wicked Khurramites (Khurramiyyah). It has reached me that great wealth has come to some of my followers. So whoever has any of that with him should deliver it to my agent. And whoever is far away should intend to deliver it, even after some time, for the intention of the believer is better than his action. As for what I make obligatory every year from yields and landed estates, it is half of one-sixth, meaning one-twelfth, from the one whose estate covers his expenses. But whoever’s estate does not cover his expenses, then there is no half of one-sixth upon him, nor anything else."