Kitab al-Kafi
In Kitab al-Kafi, Imam Musa al-Kadhim was asked for the interpretation of 57:11 Who is it that would loan Allah a goodly loan so He will multiply it for him and he will have a noble reward? to which he replied , " this was revealed about payment to the Imams. One dirham paid to the Imam is greater in weight than the mountain of Uhud and the reward is greater than two million dirhmas paid for other charities." Another narration states it is the "good" towards the Imam during a government of mischief.