12 Now the sons of Eli were corrupt; they did not know the Lord. 13 And the priests' custom with the people was that when any man offered a sacrifice, the priest's servant would come with a three-pronged fleshhook in his hand while the meat was boiling. 14 Then he would thrust it into the pan, or kettle, or caldron, or pot; and the priest would take for himself all that the fleshhook brought up. So they did in Shiloh to all the Israelites who came there. 15 Also, before they burned the fat, the priest's servant would come and say to the man who sacrificed, "Give meat for roasting to the priest, for he will not take boiled meat from you, but raw." 16 And if the man said to him, "They should really burn the fat first; then you may take as much as your heart desires," he would then answer him, "No, but you must give it now; and if not, I will take it by force." 17 Therefore the sin of the young men was very great before the Lord, for men abhorred the offering of the Lord.
Matthew Henry's Commentary on 1 Samuel 2:12-17
Commentary on 1 Samuel 2:11-26
(Read 1 Samuel 2:11-26)
Samuel, being devoted to the Lord in a special manner, was from a child employed about the sanctuary in the services he was capable of. As he did this with a pious disposition of mind, it was called ministering unto the Lord. He received a blessing from the Lord. Those young people who serve God as well as they can, he will enable to improve, that they may serve him better. Eli shunned trouble and exertion. This led him to indulge his children, without using parental authority to restrain and correct them when young. He winked at the abuses in the service of the sanctuary till they became customs, and led to abominations; and his sons, who should have taught those that engaged in the service of the sanctuary what was good, solicited them to wickedness. Their offence was committed even in offering the sacrifices for sins, which typified the atonement of the Saviour! Sins against the remedy, the atonement itself, are most dangerous, they tread under foot the blood of the covenant. Eli's reproof was far too mild and gentle. In general, none are more abandoned than the degenerate children of godly persons, when they break through restraints.