Studying the ideological bases for alliance between Shia and Sunni

In the present era, unity is one of the most important needs of the Islamic society, and it is necessary to examine the foundations of the belief of this important need in order to provide a solution for unity. In this article, in order to clarify foundations, the essence, and meaning of unity and coherence of Islam is expressed at first, that is attention to the common issues between religions beside disputes, and avoid of making creditable matter by enemy. the boundary of Islam, Also, is respected with the view that everyone who make declaration of Faith to Islam, his property and his honor are respected. In the issue of the bases of unity, first, the common issues between religions, as the common basis and principles, are considered; and it is natural that these principles are the same definitive issues of religion that the violation of these issues is the departure of the Islam. Another basis for unity are verses of the holy Qur’an. In this section the reasons of disagreements that are caused mostly by difference in opinion is, differences in ijtihad, and disputes due to the personal pleasures and personal preferences of them, are studied at first; Since the more discussion on difference, i.e. opposite of unity, the more understanding about the unity and its bases. Finally, we have been helped by the utterings and practices of the infallible Imams (as) as another basis for unity. This paper was made in a library method.