In what follows I show first of all that Arabic-speaking Jews and Christians lived throughout Arabia for centuries before Islam. Therefore they would have had a term for referring to God. I then note the existence of pre-Islamic Christian names that incorporated the term allâh. I also show that ancient Arabic Bible translations and the Qur’an itself reflect pre-Islamic Jewish and Christian usage of allâh to refer to God. The conclusion is that pre-Islamic Jews and Christians referred to God as allâh.
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Islamic Christian names incorporated the term allâh in reference to God
There has been speculation that some of the pre-Islamic Arab churches would have developed an Arabic-language liturgy and lectionary in the fourth or fifth century. Irfan Shahid (1989: 528f.) entertains this as a likelihood. He affirms with confidence, however, that there was pre-Islamic Christian Arabic poetry, as does Kenneth Cragg (1991). Trimingham (1979) lists five of the poets by name.16 These pre-Islamic Arab Christians would of necessity have had a word for God that they used when speaking Arabic; the poetry that survives, from Nābigha al-Dhubyānī, shows that he used the term allâh.
The hardest pre-Islamic evidence comes in the form of stone inscriptions that bear theophoric Arab names, i.e., Arabic names that incorporate a word for deity. The word one finds most often in the surviving inscriptions is ’lh, pronounced [ałłâh],17 and sometimes the shortened or Hebraic form, ’l.18 There is no evidence for a significantly different term for God used in place of this, such as Greek theos or Hebrew adonai or elohîm, although Yhwh is found on occasion, probably as part of a Jewish name.19 Harding’s Index and Concordance of Pre-Islamic Names and Inscriptions includes the following observation (1971: 907): “A feature which emerges very clearly from these lists [of theophoric names] is the overwhelming popularity of ’l, ’lh.” So while many inscriptions bore theophoric names that incorporated the names of pagan deities, there was an “overwhelming” number of theophoric names that incorporated ’lh [ałłâh] and the shortened form ’l. The widespread usage of these terms in the two centuries before Islam correlates with the well-documented spread of Christianity throughout most of Arabia that during that same period (Guillaume & Ibn Ishaq 2002 [1955]: 18).20
The Arabs used a number of scripts, but what we now call “Arabic” script was not developed until the fifth or sixth century. The earliest dated Arabic-language inscription in this “Arabic” script is the Zebed inscription. It was inscribed onto a Christian martyrion in 512 AD, where the texts are in Greek, Syriac, and Arabic.21 The Arabic text includes a name or statement in which God is referred to as alâh or allâh.22 This shows that pre-Islamic Christians were using this term in reference to God in Arabic, just as they used alâh(â) to refer to God in Syriac.
This archaeological evidence is corroborated by historical sources as well. For example, a leader of the Christians who was martyred in Najran in 523 AD is said to have been ‘Abdullah ibn Abu Bakr ibn Muhammad. Not only does he bear a theophoric name that means “servant of allâh”, he is also said to have worn a ring that said “allâh is my Lord” (Guillaume & Ibn Ishaq 2002 [1955]: 18). Similarly when four of the leading pre-Islamic men of Mecca pledged to renounce idolatry, worship God alone, and seek the true religion, it was allâh whom they acknowledged, and three of them found Him in Christianity (Ibid. pp. 99–100).23)
http://www.themicahmandate.org/2009/03/who-was-%E2%80%98allah%E2%80%99-before-islam-1/ (Archiv-Version vom 06.06.2009)