Khalid bin 'Abdullah al-Tahan خالد بن عبد الله بن عبد الرحمن الطحان · The Book of Oaths and Vows

"There is no vow and no oath concerning that which one does not possess, nor to commit sin, nor to sever the ties of kinship."

"In Al-Madinah we used to buy and sell Wasqs (of goods), and we used to call ourselves Samasir (brokers), and the people used to call us like that. The Messenger of Allah came out to us one day, and called us by a name that was better than that which we called ourselves and which the people called us. He said: 'O Tujjar (traders), your selling involves (false) oaths and lies, so mix some charity with it.'"

"They do not bring any good; they are just a means of taking wealth from the miserly."

The Messenger of Allah said: "There is no vow at a moment of anger and its expiation is the expiation for an oath." It was said: "Az-Zubair did not hear this Hadith from 'Imran bin Husain."