Man is a ‘tripartite’ being composed of the spirit the carnal self and the body. These three elements are so closely interrelated that neglecting one results in failure to achieve perfection. Man has accordingly been endowed with three essential faculties namely the spiritual intellect reason and will.
During his lifetime man experiences a continual inner struggle to choose between good and evil right and wrong. The motor of this struggle is the will as directed by reason. However human reason can be swayed by carnal desires personal feelings interests and such emotions as anger and rancor so it needs as its guide the spiritual intellect. The spiritual intellect including conscience is the source of moral values and virtues.
Historically it is the Divinely revealed religions that have determined what is right and wrong on the authority of their Revealer namely God and of the character of the Prophets who conveyed first Revelation.
Because of his worldly nature man can be too obedient a servant of his lusts. When such men as are captive to their lusts gain enough power to rule over their fellows they light fires of oppression on the earth and reduce the poor and the weak to slaves or servants. Human history is full of such instances. However as God is All-Just and never approves oppression. He sent His Prophets in certain phases of that history in order to guide and correct the individual and collective life of mankind. All of the Prophets came with the same doctrine the fundamentals of which are believing in One God. Prophethood the Resurrection. Angels. Divine Scriptures and Divine Destiny and worshipping God. All of the Prophets also conveyed the same moral principles. In this sense all the Divine religions are one and the same but the flow of history through some epochs varying in cultural geographical social and economic conditions required different Prophets to be sent to each nation and certain differences to be made in the acts and forms of worship and in the subdivisions of the law—until such time as these conditions allowed that the Seal of the Messengers could be sent and the religion completed so that in its essentials it sufficed thenceforth to solve all the problems humankind will encounter until the end of time and be applicable in all conditions. (There is an important point to be added in this connection. When a Prophet passed away his nation over time altered some of the principles of his religion borrowed some polytheistic elements from pagan practices and went astray thus corrupting the Divine religion. This historical fact was another reason for the Prophets being sent one after the other over the course of time).