What is the way for a Muslim to become strong and capable of defending himself without practicing forbidden martial arts, knowing that those who practice these arts cannot be defeated except by training like them?

The practice of boxing as it is commonly known today, and similar combat sports that involve harm and injury to the opponent, is not approved by either Sharia (definition) or reason.

However, if boxing and other combat sports are free from Sharia prohibitions such as inflicting harm on oneself or others, neglecting prayers, or exposing one's 'awra, and their purpose is to strengthen the body and for self-defense, then they become permissible.

It is stated in the book "Islamic Fiqh and its Proofs" that professional wrestling, boxing, and similar sports are forbidden due to the harm they cause to human or animal life. Islam prohibits such deviant sports because they constitute a blatant violation of the Prophet's (peace be upon him) saying: "If one of you fights, let him avoid the face."

If there is no harm to either party in boxing or wrestling, it is permissible. Likewise, it is permissible if it involves training a person in strength, combat, and self-defense. Indeed, the Messenger of Allah (peace be upon him) wrestled Rukana and defeated him.

Physical strength alone is not sufficient; strength of heart must accompany it, as courage revolves around it. Courage is not merely physical strength, for a man may be physically strong but weak in heart. Rather, it is the strength and steadfastness of the heart. The praiseworthy form of courage is that which is accompanied by knowledge and understanding, without the recklessness of one who does not think or distinguish between what is praiseworthy and what is blameworthy.