Ikrama عكرمة · The Book of Marriage

"A previously married woman should not be married until her permission has been sought, and a virgin should not be married until her consent is sought." They said: "O Messenger of Allah, how does she give her permission?" He said: "Her permission is if she keeps silent."

"The Messenger of Allah said: 'What differentiates between the lawful and the unlawful is the Duff, and the voice (singing) for the wedding.'"

"I heard Muhammad bin Hatib say: 'What differentiates between the lawful and the unlawful is the voice (singing).'"