It is Meccan, and its verses are 8. "It was revealed after the forenoon." 'In the name of Allah, the Most Gracious, the Most Merciful.'

He asks about the negation of the explanation in a way of denial, so it implies the affirmation and obligation of the explanation. It is as if it were said: We have expanded your chest for you. Therefore, it is followed by: We have placed, considering the meaning. The meaning of: We have expanded your chest:

We have made it spacious enough to encompass the entirety of prophethood and the call to both worlds. Or until it could bear the hardships that you may face from the disbelievers of your people and others: or we have expanded it with what we have deposited in it of knowledge and wisdom, and we have removed from it the constriction and hardship that comes with blindness and ignorance. And from Al-Hasan: it is filled with wisdom and knowledge. And from Abu Ja'far Al-Mansur, he read: Did We not expand for you, with the opening of the ح (hāʾ). And they said: Perhaps he pronounced the ح in a way that elongated it in its articulation, so the listener thought he opened it. And the burden that weighed down his back - meaning it burdened him with the opposite, which is the sound of being unburdened and released from its weight - is a metaphor for what was heavy upon the Messenger of Allah, blessings and peace be upon him, and distressed him from his shortcomings before prophethood. Or from his ignorance of the rulings and laws. Or from his eagerness for the Islam of those who were most obstinate among his people and his anxiety. And the removal from him: that he was forgiven, or that he was taught the laws, or that his excuse was made clear after he had reached and attained. And Anas read:

And We have loosened, and We have removed your burden. And Ibn Mas'ud read: And We have removed your burden from you. And the raising of your mention: that it is coupled with the mention of Allah in the testimony of faith, the call to prayer, the establishment of prayer, the testimony, and in many places in the Qur'an: "And Allah and His Messenger are more deserving of being pleased with them," and "And whoever obeys Allah and His Messenger," and "Obey Allah and obey the Messenger," and in naming him the Messenger of Allah and the Prophet of Allah, and from it his mention in the books of the earlier ones, and the taking of the prophets and their nations to believe in him. If you say: What is the benefit of the addition of 'for you,' while the meaning is complete without it?

I say: In the addition of 'for you' there is a way of ambiguity and clarification, as if it were said: Did We not expand for you, so he understood that there was something expanded, then it was said: your chest, so it clarified what was previously ambiguous. Likewise, 'for you' your mention and 'from you' your burden.