1 Samuel 2:30 - 33

"'Therefore the Lord, the God of Israel, declares: "I promised that members of your family would minister before me forever. But now the Lord declares: Far be it from me! Those who honor me I will honor, but those who despise me will be disdained. The time is coming when I will cut short your strength and the strength of your priestly house, so that no one in it will reach old age, and you will see distress in my dwelling. Although good will be done to Israel, no one in your family line will ever reach old age. Every one of you that I do not cut off from serving at my altar I will spare only to destroy your sight and sap your strength, and all your descendants will die in the prime of life"'" NIV translation

With failed responsibility comes penalties. The penalty for Eli's family was that they would all die at a young age. This is a reminder to us that we are not guaranteed a tomorrow on this earth.

1 Samuel 2:34

"'"And what happens to your two sons, Hophni and Phineas, will be a sign to you - they will both die on the same day."'" NIV translation

The Lord was going to make an example of Eli's two sons. With both of them dying on the same day, it would obviously be a judgment from the very hand of God.