(52–54) “Say: Have you considered that, if it is from Allah and you then disbelieve in it, who could be further astray than one who is in extreme opposition? * We shall show them Our signs throughout the horizons and within themselves until it becomes clear to them that it is the truth. Is it not enough that your Lord is Witness over all things? * Behold, they are in doubt about meeting their Lord. Behold, He encompasses all things.”
That is, “Say” to those who deny the Quran and hasten into disbelief: “Have you considered that, if” this Quran is “from Allah,” without any doubt or uncertainty, “and you then disbelieve in it, who could be further astray than one who is in extreme opposition?” That is, one who obstinately opposes Allah and His Messenger. The truth and the right course became clear to you, yet you turned away from it—not toward truth, but toward falsehood and ignorance. You would then be the most misguided and unjust of all people.
If you say otherwise, or doubt its authenticity and truth, Allah will establish the proof for you and show you some of His signs throughout the horizons, such as the signs in the heavens and the earth and the momentous events that Allah Most High brings about, all of which point the discerning person to the truth.
“And within themselves”: in the wondrous signs of Allah, the marvels of His creation, and the brilliance of His power contained in their bodies; and in the punishments and exemplary chastisements that befall the deniers, as well as the victory granted to the believers. “Until it becomes clear to them,” through those signs and with a clarity admitting no doubt, “that it is the truth,” and that everything it contains is true.
He, Most High, has indeed done so: He has shown His servants signs through which it became clear to them that it is the truth. Yet Allah alone enables whomever He wills to attain faith and forsakes whomever He wills.
“Is it not enough that your Lord is Witness over all things?” That is, is Allah Most High’s testimony not sufficient proof for them that the Quran is true and that the one who brought it is truthful? He has attested to its truth—and He is the truest of witnesses—and He supported and granted victory to the one who brought it, with a victory that confirms His verbal testimony for anyone who may doubt it.
“Behold, they are in doubt about meeting their Lord.” That is, they doubt the Resurrection and the Day of Judgment. In their view, there is no abode but this worldly life; therefore, they do not work for the Hereafter or give it any heed. “Behold, He encompasses all things” in knowledge, power, and might.
The commentary on Sūrat Fussilat is complete
—by His grace, Most High—