Why don't monotheistic religions have just one name for God? Polytheistic religions have many names for their gods because they have many gods; and each god has one or more names. But if you worship only one Deity why give it a name at all, if it is the only one? The universal, non-material, force of attraction is called gravity; and there is no need for an individual name for it, in any of the world's language.

Monotheists call God by a name because we believe that the Divine is not an impersonal, universal force or  power: for the Divine One is a personality. A unique, disembodied, undying, always creative personality, who cares about the whole created world. We even use a pronoun of gender, although God includes both genders, because we do not wish to refer to the Divine One, as it.

The Qur'an tells us (17:110) “Say, "Call upon Allah or call upon Ar-Rahman/Ha Rakhaman, the Most Merciful. Whichever [name] you call - to Him belong the best names." And do not recite your prayer [too] loudly or [too] quietly, but seek a way in between.”

For those religions that trace their prophets back to Prophet Abraham, and his two sons Ishmael and Isaac; the many names or appellations (titles and descriptions) of God simply describe different aspects or attributes of the one God's multifaceted personality.

Thus, to say that God is a King or a Judge describes one of many ways God acts. To say that God is the Merciful-Compassionate One is to describe one of many character or personality traits of the one and only God.

While each name is only one of the many appellations of the one universal creator of space and time; both Islam and Judaism also have one Divine name that is always deepest within the believer's heart and soul.

In English the word God is not the name of the one and only God like Allah or YHVH. It is the generic term for any and every deity, similar to the West Semitic root word EL; as in Sumerian and Akkadian, Ellil-Enlil, in Hittite and Hurrian as Ellel, in Hebrew El-Elohim in Arabic as Al-Ilahi, the God or Allat, a pre Islamic Goddess, one of three daughters of Al-Ilah worshiped in Palmyra as Allat and referred to by Herodotus as Alilat, and worshiped as Allatu by North African Carthaginians.

This name, Allah for Muslims and YHVH for Jews, differs from all the other names that are just  philosophical terms for various universal aspects or important roles of God. This Divine name has a very intimate  meaning for each religious community of believers; that is lacking in all the other names.

This personal name is connected to the covenant that the one God made with Moses (YHVH) and with Muhammad (Allah), as well as Noah, Abraham and Jesus (Qur'an 33:7).

Because the Qur'an is filled with beautiful Arabic poetry; it is not surprising that the the Qur'an is also filled so many beautiful names of God.

Because the Jewish tradition reaches back more than thirty five centuries; it is not surprising that Jews have focused on additional names for God over those many centuries.

Yet, because all the many names of God, call upon the same One God, it is also not surprising that many of the 99 beautiful names of God in Muslim tradition also appear in Jewish tradition, which sometimes refers to the 70 names of God (Midrash Shir HaShirim and Midrash Otiot Rabbi Akiba).

Since Arabic and Hebrew are brother languages; in some cases the names even sound alike:
Arabic                 Hebrew                                               English
Ar-Rahman,        Ha Rakhaman,                            The Compassionate One;
Ar-Rahim.           El Rakhum,                                 The Merciful One;
Al-Quddus,         Ha Kadosh,                                  The Holy One;
Al-Bari,               Ha Boray,                                    The Creator;
Al-Aliyy,             El Elyon,                                     The Most High;
As-Salam,           Oseh HaShalom,                          The Peacemaker,
Malik ul Mulk,   Melek Malkay Melakim,            The King/ruler over all the kingdom/kings;
Al-Muhyi,           Ha Michayah,                              The Giver of Life;
Al-Mumit,           Ha Maymeet,                               The Taker of Life.

Most of the similarities between Jewish and Muslim appellations of God are not due to linguistics alone. They reflect similar philosophical views of God's various attributes.

However, since for more than twelve centuries, the only ongoing monotheistic religious community in the world existed within the Jewish People, God's universal attributes were frequently expressed in the Hebrew Bible in terms of His activity and relationship to Israel.

For example, Elohei kol basar, the God of all flesh (Jeremiah 32:27) is usually referred to as Elohei Yisrael or Elohei of Abraham, Isaac, and Jacob (Exodus 3:15)

Thus, Prophet Isaiah refers to both The Holy One (Isaiah 40:25) and The Holy One of Israel (Isaiah 1:4, 5:19) and Prophet David refers to both  El Yisrael The God of Israel (Psalm 68:36) and El HaShamayim The God of the Heavens (Psalm 136:26).

Although in every generation there could have been many individuals who worshipped the One God, who was indeed the God of all humans; yet for very many generations only one group of people maintained a continuous monotheistic community. This is why all of the Biblical prophets speak of Elohei Yisrael- the God of Israel, or Elohei-God of Abraham, Isaac, and Jacob

Of course, just as one parent can love, protect, and judge many children, the One God of Israel is also the one God of the whole world, So Ezra, the most narrowly focused of prophets, uses both Elah Yisrael-God of Israel (Ezra 5:1) and Elah Sh'maya V'Arah- God of Heaven and Earth (Ezra 5:11).

Since Judaism is a very close, yet different religion from Islam, there are also several Jewish names for God's attributes that are not found among the 99 names that appear in the Qur'an.

The words El, Elah, Elohei and Elohim are all pre Abrahamic west Semitic generic terms for a God or for many Gods. In these various forms they appear almost 3,000 times in the Hebrew Bible.

But the most important name of the one God, the name that God himself reveals to Moses at the burning bush, is YHVH: which appears more than 6,800 times in the Hebrew Bible.

In Exodus 3:13-15, Moses said to God, “If I go to the Israelites and tell them, ‘The God of your fathers has sent me to you,’ and they ask me, ‘What is his name?’—what should I say to them?” And God said to Moses, “Ehyeh asher Ehyeh”.

Ehyeh is the verb “to be” future tense singular and means I will/could/might/may be/become Who I may/could/will/might be/become i.e. Ehyeh is The God of Potentialities, The God of Possibilities, The Living God of Becoming and Transforming, the One who can liberate Israel from bondage in Egypt.

Unfortunately, the Greek and Latin translations of this verse were influenced by the Greek philosophical idea that God was similar to a permanent ideal form (like an equilateral triangle) or an unmoved mover, and is not like a living personality.

Since they thought God must be a static unchanging being. they mistranslated “Ehyeh asher Ehyeh' as 'I am who I am' rather than its plain meaning of 'I can be whatever I should be to redeem you” i.e. God Almighty

The Torah continues, “And God said, “You must say this to the Israelites, “I am” (the usual false translation for God's self revealed name) has sent me to you.’” God also said to Moses, “You must say this to the Israelites, Ehyeh, the God of your fathers, the God of Abraham, the God of Isaac, and the God of Jacob—has sent me to you. This is my name forever, and this is my memorial from generation to generation.’ (Exodus 3:13-15)

When Jews speak of God in the third person, God's name is YHVH-- "the One who causes being and becoming, the One who brings potentials into existence."

This name (YHVH) was spoken publicly from the time of Moses and throughout the 3½ centuries of the 1st Temple of Solomon. But diring the period of the 2nd  Temple it was pronounced as Adonai (Lord) because of the feeling that God's actual Holy name was too holy to utter audibly.

In later centuries even the substitution was considered too holy to utter; and the custom among pious Jews till this day is not to use any name for God at all (except in prayer); but to say HaShem--the name (of God) when speaking about God. Thus, while Muslims love to voice Allah's name, Jews avoid voicing God's name (YHVH) even in prayer.

YHVH replaced a much older name of God: El Shaddai. Exodus (6:2-3) relates: God also said to Moses, “I am YHVH. I appeared to Abraham, to Isaac and to Jacob as El Shaddai, but by my name YHVH I did not make myself fully known to them.”

In the whole Hebrew Bible the full appellation 'El Shaddai' is used only in connection with Abraham, Isaac and Jacob. Shaddai by itself appears 31 times in the ancient book of Prophet Job, who was not Jewish, and in a few other poetic passages.

In the Greek translation of the Torah, El Shaddai was erroneously translated Pantokrator, all powerful/omnipotent, instead of  'The God who is sufficient”. The Greek philosophical idea of omnipotence leads to the false contradiction between God's power and human free will.

But God is indeed, more than sufficient. God is and will always be YHVH, the God who enables human hopes of future possibilities of improvement to become realized.

El Shaddai can also be translated as the Nourishing God because the Hebrew word Shaddaim means two female breasts. This feminine image may help some women today replace the ancient image of God as an old man with a long beard; with a metaphor more representative of God's classical attribute of loving concern for His children.

One of the 99 names of Allah in the Qur’an is Al Shakur— "The Appreciative One." There are several verses of the Qur'an which speak of God as appreciative: “If anyone willingly does what is good, God is appreciative and cognizant. (Quran 2:158) and “Why would God punish you if you are grateful and faithful, since God is most appreciative, most cognizant?” (Quran 4:147)

I think this is one of the most profound names of Allah in the Qur’an. It not only refutes the erroneous doctrine of ‘original sin’; it also reminds us that Allah’s generosity always rewards good efforts much more than He punishes bad acts: “As God will pay them their due and more, from the Divine bounty, for God is most forgiving, most appreciative. (Quran 35:30)

Rabbi Maller’s web site is: rabbimaller.com Rabbi Maller’s book ‘Judaism and Islam as Synergistic Monotheisms: One Rabbi's Reflections on the Profound Connectedness between Islam and Judaism’ (31articles by Rabbi Maller first published by Islamic web sites) is for sale ($15) on Amazon and Morebooks.