Judaism, Christianity, and Islam are monotheistic religions, namely they believe that there is only one God. Jews and Muslims greatly stress the oneness and unity of God. The affirmation of the oneness of God by Christians is sometimes misunderstood, because Christians believe that the one God is triune (the Holy Trinity). However, this is not a denial of monotheism but an affirmation of the complexity of the Divine Being.
All three religions believe that God is the origin and source of all that exists. God cares about the entire creation and desires the well-being of all. God is just and has provided basic rules for our guidance so that we may be good and righteous, according to God's intention. God is also merciful; by means of God's grace we are given strength to be more like what we ought to be.
The word "Allah" is the perfect description of the "One God" of monotheism for Jews, Christians and Muslims!
Long before Muhammad was born, Arabic Christians were already referring to God as Allah and millions continue do so today.
There is evidence that the word Allah existed before the birth of Prophet Muhammad for thousands of years. Prophet Muhammad's father’s name was Abdullah (which means the slave of Allah). This name was common among Arab pagans and Jews. Abdullah bin Salam was one of the first Jews to convert to Islam in Medina. When Arabs call Allah in prayer they say: “Ya Allah” or “Allahoma”. Aren't these words familiar to you? “Alleluia” and “Elohim” are the words used to call Allah in the Bible. So Elohim literally means many Allah(s). This is a known way to express dignity and respect to almighty Allah by calling Him pleural. This phenomenon is known in Hebrew, Arabic, English and other languages.
It is interesting to note that the Aramaic word "El", which is the word for God in the language that Jesus spoke, is certainly more similar in sound to the word "Allah" than the English word "God". This also holds true for the various Hebrew words for God, which are "El" and "Elah", and the plural form "Elohim". The reason for these similarities is that Aramaic, Hebrew and Arabic are all Semitic languages with common origins. It should also be noted that in translating the Bible into English, the Hebrew word "El" is translated variously as "God", "god" and "angel"! This imprecise language allows different translators, based on their preconceived notions, to translate the word to fit their own views. The Arabic word "Allah" presents no such difficulty or ambiguity, since it is only used for Almighty God alone.
Additionally, in English, the only difference between "god", meaning a false god, and "God", meaning the One True God, is the capital "G". In the Arabic alphabet, since it does not have capital letters, the word for God (i.e. Allah) is formed by adding the equivalent to the English word "the" (Al-) to the Arabic word for "god/God" (ilah). So the Arabic word "Allah" literally it means "The God" - the "Al-" in Arabic basically serving the same function as the capital "G" in English. Due to the above mentioned facts, a more accurate translation of the word "Allah" into English might be "The One -and-Only God" or "The One True God".
By Nouran Radwan