Answer
Thank you for your questions. I would like to start out by saying that Muslims believe that all prophets of God preached the same simple truth of the One Sovereign God.
Who Is Allah? Who Is God?
Allah is God. The name Allah is the Arabic word for God. More precisely, it is the One Eternal Creator, Lord of the whole universe. It is the same Arabic name for God that is used in the Arabic Bible.
It is pronounced almost the same in other Semitic languages: “Eloha” in Hebrew, and “Allaha” in Aramaic. According to Jesus (peace be upon him), God is One, with no partner whatsoever. I quote the following verses from the Bible:
Jesus said to him, “Away from me, Satan! For it is written: ‘Worship the Lord your God, and him only.’” (Matthew 4:10)
“Well said, teacher,” the man replied. “You are right in saying that God is one and there is no other but him.” (Mark 12:32)
“The most important one,” answered Jesus, “is this: ‘Hear, O Israel, the Lord our God, the Lord is one.’” (Mark 12:29)