Some commentators suggest that the heaviness of Eli is mentioned to create a contrast between him and the glory of the Lord. The Hebrew word translated as heavy
is the same word that can also be translated as glory.
Eli fattened himself on the choice of the offerings made to the Lord (1 Samuel 2:29). He was thus unconcerned for the Lord’s glory. Now the glory of the Lord has departed and the heaviness (glory) of Eli results in his death.1
18 A peine eut-il fait mention de l'arche de Dieu, qu'Eli tomba de son siège à la renverse, à côté de la porte; il se rompit la nuque et mourut, car c'était un homme vieux et pesant. Il avait été juge en Israël pendant quarante ans.