On one crucial point, Judaism, Islam and Christianity are in agreement. All insist that faith in God is the first requirement. But then that’s the prerequisite of any religion, isn’t it? The differences lie in the what each religion teaches about the nature of God.
Let’s take Christians. They teach that God is love. You hear that over and over again. “For God so loved the world that He gave His only begotten son …” Christians believe that by dying on the cross for our sins, God (through Jesus) showed how much He loved us. Why else would God go through all that if He didn’t?
One of the criticisms that Christians have about Islam is that Allah is not primarily a loving God. They seem to need proof that God loves us, and that that proof is provided by His sacrifice on the cross. Muslims believe that God is continually showing His love for us and that the only proof we need is 1) that He created us in the first place; 2) that He is always there for us; and 3) that He is a Merciful God. Besides, why should God have to prove anything? He is God.
It’s completely erroneous to say that Allah is not a loving God. First of all, Muslims believe that Jesus was one of the great prophets of God and that we are to heed his teachings. We accept what he taught about God’s nature. But Jesus never said that God was a Triune God. The Christian Church developed the concept of the Trinity by putting together certain things that Jesus did say with the opinions of New Testament writers and of theologians who lived centuries after Jesus.
Christians start off wrong in their dealings with Muslims when they assume that Allah is a completely different God than the one they worship. The One God is the same whether He is worshiped by Jews, Christians or Muslims. But men try to shape their understanding of God according to the tenets of the religion they follow. Jews emphasize God’s omnipotence, Christians emphasize His love and Muslims emphasize His totality.
That’s why Muslims believe that Allah has 99 names. His nature can’t simply be summed up in one sentence. He is omnipotent and loving, but He is much more than that. To be fair, Jews and Christians also believe that God’s nature is complex. And we all agree that that God is unknowable exactly because He is God. But we can also rejoice in the fact that God hasn’t left us completely in the dark about His nature.
All the People of the Book (Jews, Christians and Muslims) believe that God reveals Himself in His Book(s). Each of these religions believes that their Book is the last word on God. (But only the Qur’an truly is the last word.) That doesn’t mean, however, that we can’t learn about God from reading the other Books. We can use the Qur’an to guide us as to what has been corrupted in the Old and New Testaments of the Bible, but I think it’s important to familiarize ourselves with the pictures of God that we find there.
You can tell a lot about what a person believes about God’s nature by the rules that they follow. Jews follow the Ten Commandments which start out with God stating that He is a jealous God, and that therefore we are not to have any other Gods before Him. Christians like to sum up what Jesus taught in the phrase, “Thou art to love the Lord God with all thy heart, soul and mind, and thy neighbor as thyself.” Muslims take seriously God’s admonitions to worship and follow Him alone. All three emphasize different aspects of what God expects from us, but we can learn from them all about the God’s nature.
No one religion can say that it alone has a complete understanding of God. We need to remember that when we interact with each other.
See these charts that compare Judaism, Christianity and Islam.