Before assigning to man this vicegerency (Khilafat), Allah made it clear to him that He alone is the Lord, the Ruler and the Deity. As such, the entire universe and all the creatures in it (including man) should submit to Him alone.
Man must not think himself totally free and must realize that this earth is not his permanent abode.
He has been created to live on it only for a probationary period and, in due course, he will return to his Lord, to be judged according to the way he has spent that period.
The only right course for man is to acknowledge Allah as the only Lord, the Sustainer and the Deity, and to follow His guidance and His commands in all he does.
His sole objective should be to merit the approval of Allah.
If man follows a course of righteousness and godliness (which he is free to choose and follow) he will be rewarded in this world and the next: in this world he will live a life of peace and contentment, and in the Hereafter he will qualify for the heaven of eternal bliss, Al-Jannah. If he chooses to follow the course of godlessness and evil (which he is equally free to choose and follow), his life will be one of corruption and frustration in this world, and in the life to come he will face the prospect of that abode of pain and misery which is called Hell.
After making this position clear, Allah placed man on earth and provided the very first human beings (Adam and Eve) with guidance as to how they were to live.
Thus man’s life on this earth did not start in utter darkness. From the beginning a bright torch of light was provided so that humanity could fulfill its glorious destiny.
The very first man received revealed knowledge from Allah Himself, and was told the correct way to live.
This code of life was Islam, the attitude of complete submission to Allah, the Creator of man and the whole universe. It was this religion which Adam, the first man, passed down to posterity.
But later generations gradually drifted away from the right path.
Either they lost the original teachings through negligence or they deliberately adulterated and distorted them. They associated Allah with innumerable human beings, material objects and imaginary gods. Shirk (polytheism) became widespread. They mixed up the teachings of Allah with myths and strange philosophies and thus produced a jumble of religions and cults; and they discarded the God-given principles of personal and social morality, the Shariah.
Although man departed from the path of truth, disregarded or distorted the Shariah or even rejected the code of Divine guidance, Allah did not destroy them or force them to take the right course. Forced morality was not in keeping with the autonomy He had given to man. Instead, God appointed certain good people from among the human society itself to guide men to the right path.
These men believed in Allah, and lived a life of obedience to Him. He honored them by His revelations, giving them the knowledge of reality. Known as prophets, blessings and peace be on all of them, they were assigned the task of spreading Allah’s message among men.