Kitab al-Kafi
In Kitab al-Kafi, Ja'far al-Sadiq has narrated that Imams are not needy to what people own but rather collect religious tax on accord that Allah said, "Take from their wealth (religious tax) and charity by which you purify them and cause them to increase and invoke blessings upon them." Therefore, it is the people who need that the Imam accepts from them.