Muslims believe that Jesus was a prophet and not God, therefore it is a grave sin for a Muslim to pray to him. Allah is not the name of God, nor is it a separate God from the God of the Bible. Allah is Arabic for The God, which only specifies the "oneness" of God and not naming God. Therefore, if a Christian should pray to Allah, they are in fact praying to the same God in which they believe in; the Creator of the Heavens and Earth, the God of Abraham, Adam, Eve, Issac. The same holds true for the Jewish faith. The only issue would be praying to anyone other than God, (i.e. Jesus, Mary or Saints).
