“Indeed, your Lord knows that you stand in prayer for nearly two-thirds of the night, or half of it, or a third of it, as does a group of those with you. Allah determines the measure of the night and the day. He knows that you will not be able to keep count of it, so He has turned to you in mercy. Therefore, recite whatever is easy for you of the Quran. He knows that there will be among you those who are ill, others travelling throughout the land seeking Allah’s bounty, and others fighting in the cause of Allah. Therefore, recite whatever is easy from it; establish the prayer, give zakah, and lend Allah a goodly loan. Whatever good you send ahead for yourselves, you will find it with Allah, better and greater in reward. And seek Allah’s forgiveness; indeed, Allah is All-Forgiving, Most Merciful.” (20)

“Indeed, We have sent to you a Messenger as a witness over you, just as We sent a messenger to Pharaoh.”

“But Pharaoh disobeyed the messenger, so We seized him with a crushing seizure”—that is, a severe and weighty one: We punished him with a grievous punishment, thereby warning the disbelievers of Mecca.

“How, then, will you protect yourselves, if you disbelieve?” That is, how will you be able to protect yourselves on the Day of Resurrection when you disbelieved in this world? In other words, when you arrive on the Day of Resurrection, there will be no means by which you can protect yourselves. It was also said that it means: How will you shield yourselves from the punishment on the Day of Resurrection, and by what will you fortify yourselves against it, if you disbelieve?

“A Day that will turn children grey-haired”: their hair will be streaked with grey because of its terror and severity. This will be when Adam is told: “Rise and send forth from your progeny the contingent destined for the Fire.”

He then described the terror of that Day, saying: “The heaven will be split apart because of it”—that is, torn open for the angels to descend through it, meaning at that place. It was also said that the pronoun refers to the Lord: by His command and His awe. “His promise is sure to be fulfilled”: it will surely come to pass.

“Indeed, this” refers to the verses of the Quran—“is a reminder”: a reminder and an admonition. “So whoever wills may take a path to his Lord,” through faith and obedience.

“Indeed, your Lord knows that you stand for less than two-thirds of the night, or half of it, or a third of it.” The readers of Mecca and Kufa recited “half of it and a third of it” with the final letters in the accusative and both pronominal suffixes fully vocalized with a ḍammah; that is, you stand for half of it and a third of it. The other readers recited them in the genitive, with both pronominal suffixes fully vocalized with a kasrah, coordinated with “two-thirds.”

“And a group of those with you,” meaning the believers; they would stand in prayer with him. “Allah determines the measure of the night and the day.” Ata said: This means that knowledge of what you do does not escape Him. That is, He knows the precise measures of the night and the day, and thus knows the amount of the night for which you stand in prayer. “He knows that you will not be able to keep count of it.”