Fighting
But Allah forbids you from taking as allies those who fought you over religion, expelled you, or supported your expulsion. Whoever takes them as allies, they are the wrongdoers.
60:9Allah forbiddeth you only those who warred against you on account of religion and have driven you out from your homes and helped to drive you out, that ye make friends of them. Whosoever maketh friends of them - (All) such are wrong-doers.