The term Islam, as time went by, included the whole of the theoretical and practical constitution of the faith and as such it is interpreted by Al-Ghazzali in his Ihya-ul-ulum (p. 104, vol. I.) Islam, says he, is an expression for submission and unquestioning obedience, abandonment of insubordination, defiance and opposition. And it is in this light, indeed, that the prophet himself regarded Islam. “The Bedwins say: ‘we believe,’ Speak! you shall not ‘believe’ (only) but say we practice Islam (Aslamna).” (XLIX. 14) In Surah III. 17 (Cf. V. 79) Islam is identified with _din_ (Cf. LXI. 7-9) and the relation between the two synonyms, says Prof. Hirschfeld, is broadly discussed by Al-Shahrastani (Milal, pp. 25 to 27) and is stated to embrace the five duties, _viz._:--Of testifying to the unity of God and the Divine inspiration of Mohamed, the duties of reciting prayers, giving alms, fasting in the _Ramadhan_, and performing the pilgrimage to Mecca. The fundamental basis of Islam is the unity of God; stern, unbending monotheism and this doctrine of the unity of God is proclaimed in the Qur´an, in season and out of season and ever and anon with augmented emphasis. To associate gods with God is the most unpardonable sin and the prophet’s extensive vocabulary of vituperation is never exhausted in attacking those who associate gods with God. In Surah VI (verses 74-79) we have one of the most charming passages testifying to the unity of God:-- And remember when Abraham said to his father, Azar, thou takest those images as God? verily I see that thou and thy people are in manifest error. And so did we show Abraham the domain of the heavens and of the earth that he might be one of those who are established in knowledge. And when the night overshadowed him he beheld a star “This, said he, is My Lord” but when it set, he cried, “I love not gods which set.” And when he beheld the moon uprising “This,” said he, “is my Lord” but when it set, he said, “surely, if My Lord guide me not I shall be of those who go astray.” And when he beheld the Sun uprise, he said, “This is my Lord,” “this is the greatest” but when it set, he said “O my people I share not with you the guilt of joining gods with God.” _I verily turn my face to him who hath created the Heavens and the earth following the right religion and I am not one of those who add gods to God._