I think he traced it back to the Prophet ﷺ, who said, "When one of you dies, his place is shown to him morning and evening. If he is among the people of Paradise, then from Paradise, and if he is among the people of the Fire, then from the Fire. It is said to him, 'This is your place until you are resurrected to it on the Day of Judgment.'"
حدثنا إسماعيل أخبرنا أيوب عن نافع
أحسبه قد رفعه إلى النبي ﷺ قال إذا مات أحدكم يعرض عليه مقعده غدوة وعشية إن كان من أهل الجنة فمن الجنة وإن كان من أهل النار فمن النار يقال هذا مقعدك حتى تبعث إليه يوم القيامة
Its isnad is sahih, and it is a repeat of 4658. "His seat was shown to him" is what is established in H and K, while in M it reads "his seat was shown to me," which is a variant noted in the margin of K, and what appears here is noted in the margin of M as a variant.As for his saying, "he is of Paradise" and "he is of the Fire," this is what is established in H and M, while in K it reads "he is of the people of Paradise" and "he is of the people of the Fire," with the addition of "the people of" established as a variant in the margin of M, and it agrees with the previous narration.