The word Islam means submission to God.
The word Christian means a disciple of Jesus Christ who follows his beliefs.
Names of God
In Islam, Allah means "the God," the Forgiving, Merciful, Wise, All-knowing, Mighty, Helper, Protector, etc.
A person who is a Christian is to refer to God as their Father.
Nature of God
In Islam, Allah is one. He begets not and He is not begotten and there is none like unto Him (the term "Father" is never used in the Koran).
A true Christian believes that the Godhead is currently composed of two Beings (God the Father and His Son). Note that the Trinity is not a New Testament doctrine.
God's purpose and plan
In Islam, Allah does as He pleases.
Christians believe that the Eternal is currently working out a plan in which all humans come into the image of Jesus as His divine children.
What is a Spirit?
In Islam, a spirit is an angel or created attribute. God is not spirit.
The Bible makes it plain that God, Jesus and the angels are composed of spirit. What is called the Holy Spirit is the power by which the Eternal and Jesus Christ perform their will. When His spirit resides in a person it makes them a Christian.
God's Spokesmen
Islam believes that the Old Testament prophets, and Jesus, culminated in Muhammad. Muhammad was the paracletos (advocate).
Christianity teaches that the Old Testament prophets climaxed in Jesus, who was then followed by the apostles.
Who is Jesus Christ?
Islam teaches that Jesus is considered one of God's prophets, born through a woman named Mary and produced by the angelic power of Gabriel. Allah took Jesus while a phantom (ghost?) of him was put on the cross and crucified.
Jesus Christ, the only begotten Son of God, was miraculous conceived in the womb of Mary through the power of the Holy Spirit. Jesus, the God of the Old Testament, divested himself of all his power and glory in order to become a human and die for the sins of all mankind.
God's Written Communication
Al Koran (the recitation) of 114 suras (units) supported by many volumes of hadith (traditions). The Koran (Quran) was dictated to Muhammad by the Angel Gabriel in pure Classical Arabic. For Islam the Koran is their link to God.
For Christians the Bible, composed of Old Testament books in Hebrew and Aramaic and New Testament books in Greek, is God's inspired and authoritative communication with humans.
Nature of Man
Islam believes humans are sinless at birth with capacity for unlimited moral and spiritual progress through belief in God and faithful adherence to the teachings.
The Bible teaches that humans are born with human nature which makes them prone to sin and leads to natural enmity towards God. His grace and his Spirit gives humans the ability to repent of their evil ways and become holy.
Personal accountability
The activities of the wicked and of the saint, of the generous and of the grasping, are, according to Islam, all Allah's creation. Allah may give up to seven spirits to a man. But those who choose good will be rewarded, and evil punished.
Christianity believes all have sinned and fallen short of the glory of God. The wages of sin is death. Our Father calls on humans to choose life, become a Christian, and depart from evil.
What are believers?
In Islam, believers are referred to as "my slaves."
The Bible teaches those with God's spirit in them are his dear children (Romans 8:16).
Life after death
At the Resurrection the righteous go to the Garden of God but do not see him. Islam believes the wicked dwell forever in fire. Those considered especially righteous do not need to await the Resurrection.
True Christianity teaches that all humans will eventually be resurrected. All will have a genuine opportunity to be saved. The righteous will rule with Jesus in the Kingdom when the Eternal's throne is with men. Those who reject his way, the incorrigibly wicked, will be obliterated.
Martyrdom
"Call not those who are slain in the way of Allah 'dead.' No, they are living, only ye perceive it not" (2:154). Each martyr has 72 virgins waiting for him in Paradise (Sermon at Al-Aqsa Mosque September 9, 2001 - cf. 56:37).
Jesus warned that those who believe in him will be hated, rejected and some ultimately killed (John 16:2, James 5:6 - 7).
Enemies
"Fight in the way of Allah against those who fight against you . . . And slay them wherever ye find them" (2:190). "Lo! Allah loveth those who battle for His cause in ranks, as if they were a solid structure" (61:4).
Christians are to love their enemies and pray for them (Matthew 5:44, John 18:36).
Prayers
Ob'adah-b-Swa'met, a believer in Islam, reported that Muhammad had said that the Almighty Allah required five prayers a day.
True Christians believe they are to pray in secret and to not let anyone know about it (Matthew 6:6).
Criminal Justice
Islam states, "Retaliation is prescribed for you in the matter of the murdered" (2:178). It also states, "As for the thief, both male and female, cut off their hands" (5:38).
The belief of Christians revolve around Jesus' teaching which states, "So when they continued asking Him, He (Jesus) raised Himself up and said to them, 'He who is without sin among you, let him throw a stone at her first'" (John 8:7, see also Romans 13:3 - 4).