Is masturbation forbidden in Islam, and what are the narrations that discuss it, and is it permissible to call for its abandonment and warn against its dangers?

Masturbation is forbidden (haram (definition)). An individual should invite their community to abandon it by explaining its harms and remedies, and by guiding them to the Prophetic guidance of marriage for those who can, or fasting for those who cannot, as stated in his (peace be upon him) saying: "O young people! Whoever among you can afford to marry, let him do so, for it helps in lowering the gaze and guarding one's chastity. And whoever is not able to marry, let him fast, for fasting will diminish his sexual urge." This should be done with wisdom and good admonition. It is beneficial for the caller to join a group that can assist him.