The Messenger of Allah صلى الله عليه و سلم appointed Mu'adh ibn Jabal رضي الله عنه and Abu Musa al-Ash'ari رضي الله عنه as the leaders of the Muslims going to Yemen to preach Islam. They were each sent to two separate districts of Yemen. As they were about to leave, The Messenger of Allah صلى الله عليه و سلم spoke to them,
Remember, make things easy for the people there, do not make things difficult. Give people good news, do not provoke them to anger. Always coordinate your efforts and remain united. You will come across people who have a religion of their own. When you meet them, invite them to Tawhid (unity of God) and Risalah (Prophethood). When they accept Tawhid and Risalah, tell them that a Muslim should offer Salaah (Prayer) five times a day. When they accept this, tell them that Allah obligates Muslims to pay Zakaah (Charity) to their less fortunate brothers and sisters. The rich should also pay Sadaqah (Charity) to the poor. Remember, when they agree to give you the Zakaah, do not take the best things from their belongings. Be fearful of the curse of the oppressed. There is not barrier between it and God.
Abu Musa al-Ash'ari رضي الله عنه asked the Messenger of Allah صلى الله عليه و سلم, "O Prophet of Allah, people in our country make a drink from barley and honey. Is it permissible?"
The Prophet صلى الله عليه و سلم then replied that all those things which are intoxicants are Haram (not permissible).
[Source: Stories of the Sirah Vol. 2 - Power Belongs to Allah]
