If I believe in God and lead a moral life, why should I convert to Islam?

 

I appreciate the clarity and the honesty with which this letter has been written. I have chosen to publish it in full because it expresses the feelings of many an honest non-Muslim who may be irritated by the thought that every virtue has to be Islamic in order to be acceptable to God. Hence the accusation of patronization of God that is sometime leveled at Muslims.

 

This question can only be sorted out if we go back to basic belief. The question of believing in God is inherent in human nature. However, it is an aspect of God's grace that we do not have to rely on this intrinsic tendency in our nature to formulate our concept of Him. God Almighty sent messengers to warn humankind and educate them on how to believe in God.
All these messengers emphasized God's Oneness and formulated the same concept of the Godhead, warning their people against associating partners with Him. Messengers were sent to all nations and communities. God tells Prophet Muhammad: “You are but a warner; We have sent you as an announcer and a warner about the truth. There has been no community unless some warner has passed among them." (Quran 35: 23-4).
This means that there were numerous prophets, messengers and warners who explained to mankind how to conduct their lives in a way which would be acceptable to God. There are about twenty-five prophets mentioned by name in the Quran. However, God states in the Quran that He has mentioned some of His messengers to Prophet Muhammad, while some He has chosen not to mention. Therefore, the great teachers of humankind who strove to establish faith among their communities and to lay down concepts of morality might have been prophets and even messengers though we cannot say with any degree of certainty because it is God Himself Who can only state certainty about such matters. However, since He has chosen not to tell us about those people and their status, we cannot say anything in this connection. We simply limit ourselves to the certain knowledge God has revealed in the Quran.
God makes it clear that the Quran is His final message to humankind, and He undertakes to keep it intact for the rest of time. He says, "Indeed, it is We Who sent down the Quran and indeed We will be its Guardian" (Quran 15: 9) and "Indeed, upon Us is its collection [in your heart] and [to make possible] its recitation" (Quran 75: 17).
However, God also tells us in the Quran that earlier messages suffered distortion and alteration. This applies particularly to the Torah and the Bible. Therefore, although we believe that both of these books were originally revealed by God to Moses and Jesus (peace be upon them both), we also believe that any fundamental difference between either of them and the Quran is the result of willful distortion.

The very fact that God sent so many messengers and prophets to mankind to teach them how to believe and conduct their lives makes it clear that it is from Him Alone that we should derive our concepts of God, faith, the position of mankind and how they should believe in their Lord. The Quran denounces the pagan Arabs for adopting polytheism and believing in many deities whom they considered intermediaries between themselves and God. Although they did not reject God altogether, they felt He was too great for them to put their address to Him directly. Therefore, they associated with Him partners whom they worshipped so they could bring them nearer to God.
When we speak of believing in God, we have to acknowledge the fact that in order to be true believers, we must believe in Him in the way He likes. In short, our formulation of God should be the one He Himself has outlined through the prophets and messengers He sent in all periods of history.

There can simply be no conflict between what every one of those messengers preached about God. Different religions may offer different concepts of God, but there can only be one true concept and that is the one He Himself has laid down in His messages to mankind. Since these were subject to distortion, then that concept can only be derived from the message He guaranteed to keep intact, namely, Islam. Hence, true believers must reject any concept that is not in total agreement with the monotheistic concept of God stated clearly in the Quran.

The other part of your question tries to distinguish between a Muslim and a believer. The Quran also makes this distinction. Reflect if you will on the following verse:
"The desert Arabs say: We believe. Say: You have not believed, but say instead: We submit. Yet belief has not penetrated your hearts. If you obey God and His messenger, He will not slight you in any of your actions. God is much-forgiving, merciful" (Quran 49: 14).

The Arabic term used for ‘We submit’ is ‘aslamna’ which is the verb used to indicate acceptance of Islam. As you are probably aware, the word ‘Islam’ means ‘submission to God.’ The Quranic verse therefore distinguishes between submission and Islam, which is a practical attitude, and having faith or ‘iman’ which indicates a conscious belief and a conceptual attitude. What the faith of Islam requires of all people is far more than the practical attitude. It requires having faith deeply entrenched in one's mind and heart.

It is true that the actions of some Muslims may not give full credence to their faith. Some may not even distinguish between what is forbidden and what is lawful; they may have very little knowledge of right and wrong. The very fact that they were born into a Muslim family does not ensure their salvation. Islam requires of everyone to have a conscious belief in God, His Oneness and all His attributes. Therefore, true faith can only come through deep thinking, reflective study and a conscious acceptance of the basic principles of faith. It then requires that everyone should conduct their lives in accordance with Islamic teachings. Salvation can only be ensured through faith and action. Neither one is sufficient on its own.
There is no doubt that there are among the followers of other religions people of integrity, honesty, and good morals. Even among the pagan Arabs there were some of these. The Prophet (peace and blessings be upon him) was asked: "Who are the best people?" He gave his questioners one answer after another, but those answers were not the one they sought. He then confirmed that they were asking about the different types of people. He then said to them: "The best of them in pre-Islamic days are the best after having accepted Islam; if they would learn it properly."

We cannot subject the Quran to different interpretations. We interpret it and explain it the way Prophet Muhammad (peace and blessings be upon him) has explained to us. Otherwise, we would be imposing our views on the Quran.
And God Almighty knows best.