What is the wisdom behind the purity of a suckling boy's urine and the impurity of a girl's urine? Is music forbidden, and what is the meaning of "they will consider permissible sexual promiscuity and musical instruments"?

The urine of both a male infant and a female infant is impure (najis). The difference lies in the method of purification: for the urine of a male infant who has not yet eaten food, it suffices to sprinkle water over it (nadh), whereas the urine of a female infant must be washed. This is based on the hadith (definition): "The urine of a female infant is to be washed, and water is to be sprinkled over the urine of a male infant." Scholars have explained the leniency regarding the male infant's urine with several reasons, among them: that his urine disperses, making it difficult to wash everything it touches; that male infants are carried frequently by both men and women; and that the urine of a female is considered more impure than that of a male. Music is forbidden due to the indication of the authentic hadith in Sahih (definition) al-Bukhari: "There will be among my Ummah people who will consider unlawful sexual intercourse, silk, alcoholic drinks, and musical instruments as lawful."