2/87 — The chain and hawā
"We gave Moses the Book and sent messengers after him… Whenever a messenger brought you something your souls did not like, you were arrogant; some you called liars, and some you killed."
وَقَفَّيْنَا — root q-f-w: the nape, the back. The verb means "to come at someone's nape", that is, to send immediately after. The line of prophets is described as a caravan walking one at the other's nape. The idea of the chain in the fourth verse of the sūra takes concrete form here.
The crucial place in the verse is this: no lack of proof is given as the cause of rejection. What is given is this:
هَوَىٰ — root h-w-y: to fall, to go downward. From the same root comes hāwiya (an abyss, the place one falls into); it occurs in Sūrat al-Qāriʿa as a name of the fire. Hawā is also akin to "air" — an emptiness with nothing to hold on to.
Arabic has given desire this name, then: what pulls a person downward. The word states a direction. Indeed the Qurʾān uses this word in the context of making something a god as well: "Have you seen the one who takes his hawā as his god?" (al-Furqān 25/43) — that is, a person's making what he wants into the measure.
This verse gives the diagnosis of the whole section. Believing in part of the Book and rejecting part of it (2/85), bending the word (2/75), going round the prohibition (2/65) — the mechanism common to them all is this: the ruling is first put to hawā, and only then is one turned back to the text.
رُوحِ ٱلْقُدُسِ — the supporting of Jesus (ʿĪsā) with this spirit. The majority of the classical commentaries explain it as Gabriel (Jibrīl); the root of "quds" (q-d-s) conveys purity and cleansing.