And when you, [O Muhammad], do not bring them a sign, they say, "Why have you not contrived it?" Say, "I only follow what is revealed to me from my Lord. This [Qur'an] is enlightenment from your Lord and guidance and mercy for a people who believe."
"Ajtabā" (اجتبى) a thing means to gather it for oneself, as in "ijtamaʿahu" (he gathered it). Or, it is derived from "jabaytu ilayhi" (I collected it toward him), so "ijtabāhu" means he took it, similar to saying "juliyat ilayhi al-ʿarūs fajtalāhā" (the bride was unveiled to him, so he beheld her).
"Lawlā ijtabaytahā" (لولا اجتبيتها): Why did you not gather it yourself, as an invention of your own? This is because they used to say: "This is nothing but a lie" (Sabaʾ: 43). Or, it means: Why did you not take it as a revelation sent down upon you, as you proposed?
"Say, 'I only follow what is revealed to me from my Lord'": I am not an inventor of the verses, nor am I one who proposes them.
"These are basāʾir (insights)": This Qurʾan is basāʾir from your Lord, meaning clear proofs through which the believers become insightful (buṣarāʾ) after having been blind. Or, it is in the position of being the insights of the hearts.
"And when the Qurʾan is recited, then listen to it and pay attention, that you may receive mercy."
