Abu Dawud Book 13, Hadith Number 3022.
Narated By Abyad ibn Hammal : Abyad spoke to the Apostle of Allah (PBUH) about sadaqah when he came along with a deputation to him.
He replied: O brother of Saba’, sadaqah is unavoidable. He said: We cultivated cotton, Apostle of Allah. The people of Saba’ scattered, and there remained only a few at Ma’arib.
He therefore concluded a treaty of peace with the Apostle of Allah (PBUH) to give seventy suits of cloth, equivalent to the price of the Yemeni garments known as al-mu’afir, to be paid every year on behalf of those people of Saba’ who remained at Ma’arib.
They continued to pay them till the Apostle of Allah (PBUH) died.
The governors after the death of the Apostle of Allah (PBUH) broke the treaty concluded by Abyad by Hammal with the Apostle of Allah (PBUH) to give seventy suits of garments.
AbuBakr then revived it as the Apostle of Allah (PBUH) had done till AbuBakr died. When AbuBakr died, it was discontinued and the sadaqah was levied.