It also shows why they have been admonished to fear their "Lord"...

It also shows why they have been admonished to fear their "Lord", instead of saying "fear Allah" or using some other divine name, because the condition attributed to them, "Who created you from a single being. . . many men and women", encompasses the whole mankind and is not confined to the believers; and these are the attributes more relevant to Lordship (i.e., concerned with the affairs of managing and perfecting) and not with the attributes of worship or divinity.

The words, "Who created you from a single being and created its mate of the same (kind) ": "an-Nafs (translated here as "being") according to the dictionary and language denotes the thing itself. They say: "He came to me (nafsuhu - himself); or "He came to me ('aynuhu; - the self same); although the basis for use of these two words, "an-nafs" and "al-'ayn" in this meaning (self; same; quiddity of a thing) is etymologically different.

an-Nafs of a man is that because of which man is man; and it is the combination of soul and body in this life and only the soul in the life of al-Barzakh, as we have explained in the Commentary of the verse: And do not speak of those who are slain in Allah's way as dead; nay, (they are) alive, but you do not perceive (2:154). The context obviously shows that the words, "a single being", refer to Adam (a.s.) and "its mate" to Adam's wife.

These two were the progenitors of this species to which we all belong; and all the human beings return to the same root, to those two parents, as Allah says in other verses too: He has created you from a single being, then made its mate of the same (kind) (39:6); O children of Adam!

let not the Satan cause you to fall into affliction as he expelled your parents from the Garden 17:27); and the Satan is quoted as saying: If Thou shouldst respite me to the Day of Resurrection, I will most certainly cause his progeny to perish except a few (17:62). Some exegete has opined: The words, "a single being" and "its mate", in this verse refer to human couple of male and female in general, on which human progeny depends.

The verse in effect means: 'Allah has created everyone of you from a human father and mother, there is no difference among you in this respect.' Thus it goes parallel to the words of Allah: O you people!