Is it permissible to pray after the emission of semen—masturbation—whether inside or outside the clothing?

Masturbation is forbidden, and repentance for it is obligatory. If it results in the emission of semen, then ghusl (ritual bath) becomes obligatory, as it is a major impurity that prevents the validity of prayer. As for the semen itself, it is pure, and washing it from clothes is recommended but not obligatory.