First of all, it is to be noted that Islam, being Allah’s final message to humanity, is a comprehensive system dealing with all spheres of life; it is a state and a religion, or government and a nation; it is a morality and power, or mercy and justice; it is a culture and a law or knowledge and jurisprudence; it is material and wealth, or gain and prosperity; it is Jihad and a call, or army and a cause and finally, it is true belief and worship.
Sheikh Yusuf Al-Qaradawi, in his book How the Imported Solutions Disastrously Affected Our Muslim Nation, states the following: Secularism may be accepted in a Christian society but it can never enjoy a general acceptance in an Islamic society. The New Testament itself divides life into two parts: one for God, or religion, the other for Caesar, or the state: “Render unto Caesar things which belong to Caesar, and render unto God things which belong to God” (Matthew 22:21). As such, a Christian could accept secularism without any qualms of conscience. Furthermore, Westerners, especially Christians, have good reasons to prefer a secular regime to a religious one. Their experience with “religious regimes” – as they knew them – meant the rule of the clergy, the despotic authority of the Church, and the resulting decrees of excommunication and the deeds of forgiveness, i.e. letters of indulgence.
For Muslim societies, the acceptance of secularism means something totally different. Since Islam is a comprehensive system of `Ibadah (worship) and Shari`ah (legislation), the acceptance of secularism means abandonment of Shari`ah, a denial of the Divine guidance and a rejection of Allah’s injunctions. It is a total falsification to claim that Shari`ah is not proper to the requirements of the present age. The acceptance of a legislation formulated by humans means a preference of the humans’ limited knowledge to the Divine guidance: [Say! Do you know better than Allah?] (Al-Baqarah 2: 140). For this reason, the call for secularism among Muslims is atheism and a rejection of Islam. Its acceptance as a basis for rule in place of Shari`ah is a downright apostasy. The silence of the masses in the Muslim world about this deviation has been a major transgression and a clear-cut instance of disobedience that has led to a sense of guilt, remorse, and inward resentment, all of which have generated discontent, insecurity, and hatred among committed Muslims because such deviation lacks legality.
Secularism is compatible with the Western concept of God which maintains that after God had created the world, He left it to look after itself. In this sense, God’s relationship with the world is like that of a watchmaker with a watch: he makes it then leaves it to function without any need for him. This concept is inherited from Greek philosophy, especially that of Aristotle who argued that God neither controls nor knows anything about this world. This is a helpless God as described by Will Durant. There is no wonder that such a God leaves people to look after their own affairs. How can He legislate for them when He is ignorant of their affairs? This concept is totally different from that of Muslims.
We Muslims believe that Allah, Glory be to Him, is the sole Creator and Sustainer of the Worlds. He is Omnipotent and Omniscient; that His mercy and bounties encompass everyone and suffice for all. In that capacity, Almighty Allah revealed His divine guidance to humanity, made certain things permissible and others prohibited, commanded people observe His injunctions and to judge according to them. If they reject this guidance and follow their own whims and man-made laws, then they commit transgression against Allah’s laws.