Man is not created by Almighty Allah in vain, but he is SUREly created to be His vicegerent (Khalifah) on the earth to build and live on it. So in order to fulfil such a task of vicegerency (khilafah) or (istikhlaf), it is necessary to have a comprehensive planned project, and this great principled project should be brought about and conveyed properly by way of the call or invitation to Allah Almighty with SURE knowledge. Regarding this aspect Allah has said in the Glorious Qur’an:"Say: This is my way: l call to Allah with SURE knowledge, l and those who follow me - Glory be to Allah! - and l am not of the idolaters (polytheists). (12:108).