9:108Do not stand in it, ever. A mosque founded upon piety from the first day is worthier of your standing in it. In it are men who love to be purified. God loves those who purify themselves.

9:122It is not advisable for the believers to march out altogether. Of every division that marches out, let a group remain behind, to gain understanding of the religion, and to notify their people when they have returned to them, that they may beware.