If a Muslim is captured, does he become a slave?

Question:
He says: Honorable Shaykh, may Allah grant you success. If Muslims fight in the lands of the disbelievers and some Muslims are found among them, and these Muslims are captured, do they become slaves, or is this specific to the disbelievers?

Answer:
They do not enslave Muslims; rather, it is the opposite: they are the ones who are enslaved because they disbelieved in Allah (Mighty and Majestic), so Allah punished them and imposed slavery upon them. The cause is disbelief. For this reason, they say that slavery is a legal incapacity that attaches to a person, and its cause is disbelief. As for those who are plundered and taken, who may be the sons of Muslims and are free, this is not permissible. This is one of the major sins: for a person to deprive a free person of his freedom without a legal cause, or to sell him and consume his price. Among the three for whom the Messenger (peace and blessings be upon him) will be the adversary on the Day of Resurrection is a man who sold a free person and consumed his price. So slavery has only one cause, which is disbelief, or through plunder, robbery, and abduction. Yes.