A man of God said the Lord would cut off strength from Eli’s house so that none would grow old. As a sign, both of Eli’s sons would die on the same day. 1 Samuel 2:31–34
In 1 Samuel 2:27–36 an unnamed “man of God” confronts Eli with a message from Yahweh. The speech recalls how Eli’s priestly line was chosen and supported, then accuses Eli of honoring his sons above Yahweh by benefiting from offerings. This passage sits inside a larger opening section where two family lines are contrasted: Hannah’s child Samuel is growing in Yahweh’s presence, while Eli’s sons misuse priestly power at the sanctuary (2:11–26).
This speech presents priesthood as both a gift and a responsibility. Yahweh reminds Eli that Eli’s ancestral “house” was chosen, brought near to the altar, and materially supported by Israel’s offerings (verses 27–28). The same system that provided honor and food also created an accountability problem when those offerings were abused (verse 29).
A careful answer keeps the immediate passage, the book's argument, and the whole-Bible storyline together, so the question is answered in context instead of as a detached idea.
Start with 1 Samuel 2:31-34, then read the surrounding section so the answer stays connected to the passage's flow.
31Behold, the days come, that I will cut off your arm, and the arm of your father`s house, that there shall not be an old man in your house.
32You shall see the affliction of [my] habitation, in all the wealth which [God] shall give Israel; and there shall not be an old man in your house forever.
33The man of yours, [whom] I shall not cut off from my altar, [shall be] to consume your eyes, and to grieve your heart; and all the increase of your house shall die in the flower of their age.
34This shall be the sign to you, that shall come on your two sons, on Hophni and Phinehas: in one day they shall die both of them.