It is the Lord - Compare the devout submission of Aaron Leviticus 10:3, and of Hezekiah 2-Kings 20:19. And, for the highest conceivable submission to the will of God, compare Luke 22:42.

Samuel told him every whit - Our word whit, or wid, comes from the Anglo-Saxon, which signifies person, thing, etc.; every whit is every thing. The Hebrew את כל הדברים et col haddebarim, "all these words."
It is the Lord - He is Sovereign, and will do what he pleases; he is righteous, and will do nothing but what is just.
Let him do what seemeth him good - There is much of a godly submission, as well as a deep sense of his own unworthiness, found in these words. He also had sinned, so as to be punished with temporal death; but surely there is no evidence that the displeasure of the Lord against him was extended to a future state.

And Samuel told him every whit, and hid nothing from him,.... And so approved himself to be a faithful prophet of God, and man of God, as he is afterwards called; the whole counsel of God is to be declared by his servants the prophets, and the ministers of his word; nothing is to be concealed, which it is the will of God should be made known, whether it be pleasing or displeasing to man:
and he said, it is the Lord; that has said it, and there is nothing to be said against it, and that will do it; and there is no resisting him: or "the Lord is he" (w); who has a sovereign right to all his creatures, and may dispose of them as he pleases; he is all wise, and does all things well; he is holy and righteous in all his ways and works, and there is no unrighteousness in him; he is faithful to his word, whether in a way of promise or threatening; and all he does to his people is in love, mercy, and kindness:
let him do what seemeth him good; not what seems good to men, or is so in their esteem, but what seems good to the Lord, who knows what is best for his people, and can do nothing but what is good; all is good he does; there is nothing but goodness in him, and nothing but goodness comes from him; he does good, and nothing else, and even when he afflicts his people; all he does is well done in creation, providence, and grace: and Eli's desire is, that he would fulfil the good pleasure of his will; he appears to be in an excellent temper, not surly and morose, taking it ill that such a message should be sent him by a child; nor was he unaffected with the case of his family, but humbly submitted to the will of God, and acquiesces in it as good, and neither arraigns his justice, nor murmurs at his providences.
(w) , Sept. "Dominus ipse", Montanus.

It is the Lord - This severe sentence is from the sovereign Lord of the world, who hath an absolute right to dispose of me and all his creatures; who is in a special manner the ruler of the people of Israel, to whom it properly belongs to punish all mine offences; whose chastisement I therefore accept.