How Did the Prophet (ﷺ) See People in Paradise and Hell?
The Prophet (peace be upon him) said:
"I looked into paradise and saw that the majority of its people were the poor, and I looked into the Fire and found that the majority of its people were women." [Agreed upon]
Commenting on this hadith, Ibn al-Malik al-Karmani (d. 854 A.H.) states in his Sharh al-Masabeeh, vol. 5, pp. 407-408:
فإن قيل: إن أهلَ الجنة والنار قبلَ يوم القيامة إما أحياءٌ أو أمواتٌ لم يُبعثوا، فكيف رآهم رسول الله ﷺ؟ قلنا: يحتمل أنه أراد بالماضي المستقبل، أو رأى أرواحَهم، أو أن الجنَّةَ والنارَ مُثِّلَتَا له بصورتهم يومَ القيامة، كما قال يومًا: «رأيت الجنَّةَ والنارَ في عرض هذا الحائط»؛ أي: مثالَهما
If it is said: "The inhabitants of Paradise and Hell before the Day of Resurrection are either alive or dead and have not been resurrected, so how did the Prophet Muhammad (peace be upon him) see them?" We say: It is possible that he referred to the future as the past, or he saw their souls, or that Paradise and Hell were presented to him in their future forms on the Day of Resurrection, as he once said, "I saw Paradise and Hell in the view of this wall,"[1] meaning their exemplars.
[1] This hadith is found in both Bukhari and Muslim.