Is it permissible to continue teaching Arabic to a Jehovah's Witness pastor, knowing that he intends to use it to convert Arabs to Christianity? And would my continued teaching of him be considered a deception from Satan? What is the best course of action to take with him?

The organization "Jehovah's Witnesses" is a secret organization, Christian in appearance but Jewish in essence. It advocates for moral chaos, does not believe in the afterlife, and has extensive activity worldwide, especially in Islamic countries. It is not permissible for a Muslim to deal with them concerning their activities. However, it is permissible to work for them in other fields if the work is permissible. As for teaching them the Arabic language, it is not permissible if the purpose is to invite Arabs to their religion, based on the Almighty's saying: "And do not cooperate in sin and aggression." It is not necessary to teach this man Arabic to invite him to Islam; rather, he should be invited and advised. The apparent situation indicates that this man is not devoid of animosity towards Islam; otherwise, he would have embraced it.