Tafsir of Al-Hijr 15:52

(When they entered upon him): It is in the accusative case as an object of a suppressed verb, coordinated with (Nabbih/Inform)—meaning: "and mention the time of their entry upon him." Alternatively, it is an adverbial modifier for "guests" (dayf), based on it being an infinitive (masdar) in its origin. Abu al-Baqa permitted it to be an adverbial modifier for it, based on its status as an infinitive in the present, annexed to its object, as the implied meaning would be "the companions/hosts of the guests," as you have heard from al-Nahhas and others. It may also be an adverbial modifier for "news" (khabar), annexed to "guests" (dayf), meaning: "the news of the guests of Abraham at the time of their entry upon him."

(Then they said): Upon that: (Peace). This is a segment of a sentence related by the verb "said" and is not in the accusative case due to it. That is: "I grant peace, a peace of safety," or "We grant peace, a peace of greeting." It is said: It is an adjective for a suppressed infinitive, the implication being: "Then they said a saying of peace."

(He said, "Indeed, we are afraid of you"): That is, fearful; for wajal (fear/trepidation) is the agitation of the soul due to the anticipation of something unpleasant. This statement of his—peace be upon him—was, according to more than one scholar, after he had brought near to them the roasted calf and they did not eat from it; for it was the custom that if a guest did not eat from what was presented to him, it was thought that he had not come with good intentions.

It is also said: It was at the beginning of their entry, as they had entered upon him—peace be upon him—without permission and at a time when one is not usually visited. This has been countered by the argument that if that were the case, they would have answered him then with the answer they gave later, and he—peace be upon him—would not have offered them food. Furthermore, the Almighty’s saying, "But when he saw their hands did not reach it, he distrusted them and felt from them apprehension," is clear in support of the first view. Perhaps this explicit declaration was after their refusal to sit.

It is also said: It is possible that the "saying" here is metaphorical, in that the signs of fear had become apparent upon him—peace be upon him—until he became like one who had explicitly uttered it. The bringing of the food was not mentioned here, suffice it to its mention in another place, just as his returning the greeting of peace to them was not mentioned for the same reason. What is of benefit to you here has already been detailed in [the chapter of] Hud, so remember it.