WITH the possible exception of two or three verses, the whole of this surah was revealed in one piece, towards the close of the Mecca period - almost certainly in the last year before the Prophet's exodus to Medina. The title Al-An'am ("Cattle") is derived from several references, in verses 136 ff., to certain pre-Islamic superstitions concerning animals which the Arabs used to dedicate to their various idols. However ephemeral those idolatrous beliefs and practices may appear in the light of later Arabian history, they serve in the Qur'an as an illustration of man's propensity to attribute divine or semi-divine qualities to created beings or imaginary powers. In fact, most of this surah can be described as a many-sided argument against this tendency, which is by no means confined to openly polytheistic beliefs. The core of the argument is an exposition of God's oneness and uniqueness. He is the Prime Cause of all that exists, but "no human vision can encompass Him" (verse 103), either physically or conceptually: and, therefore, "He is sublimely exalted above anything that men may devise by way of definition" (verse 100). Consequently, any endeavour to "define" God within the categories of human thought, or to reduce Him to the concept of a "person", constitutes a blasphemous attempt at limiting His infinite existence. (To avoid a conception of God as a "person", the Qur'an always varies the pronouns relating to Him: He is spoken of - frequently in one and the same sentence - as "He", "I" and "We"; similarly, thepossessive pronouns referring to God fluctuate constantly between "His", "My" and "Ours.) One of the outstanding passages of this surah is the statement (in verse 50) to the effect that the Prophet is a mere mortal, like all other human beings, not endowed with any supernatural powers, and "following only what is revealed to him". And, finally, he is commanded to say (in verses 162-163): "Behold, my prayer, and all my acts of worship, and my living and my dying are for God alone ... in whose divinity none has a share."