In that day I will perform against Eli all things which I have spoken concerning his house: when I begin, I will also make an end.

In that day I will raise up against Heli all the things I have spoken concerning his house: I will begin, and I will make an end.

In that day I will perform against Eli all that I have spoken concerning his house; I will begin and make an end.

In that day I establish unto Eli all that I have spoken unto his house, beginning and completing;

In that day I will do to Eli everything which I have said about his family, from first to last.

In that day, I will raise up against Eli all the things that I have spoken over his house. I will begin, and I will finish.

When I begin - literally, as in the margin: meaning, I will go through with the performance from first to last.

I will perform - all things which I have spoken - That is, what He had declared by the prophet, whose message is related 1-Samuel 2:27, etc.
When I begin, I will also make an end - I will not delay the execution of my purpose: when I begin, nothing shall deter me from bringing all my judgments to a conclusion.

In that day I will perform against Eli all things which I have spoken concerning his house,.... Or family, that is, by the man of God, 1-Samuel 2:27 as that he would cut off the strength of it, that there should not be an old man in it; and such as remained should be reduced to the utmost poverty and meanness; this shows that that prophecy was antecedent to this, contrary to the sense of some:
when I begin, I will also make an end; not immediately, and at once, but by degrees; he began in the death of Hophni and Phinehas, and went on in the slaughter of Abimelech, and the eighty five priests at Nob, in the times of Saul, and finished in the thrusting out of Abiathar from the priesthood, in the times of Solomon, whereby that family was brought to disgrace and poverty.

On that day I will perform against Eli all that I have spoken concerning his house (see 1-Samuel 2:30.), beginning and finishing it," i.e., completely. דּבּר את־אשׁר הקים, to set up the word spoken, i.e., to carry it out, or accomplish it. In 1-Samuel 3:13 this word is communicated to Samuel, so far as its essential contents are concerned. God would judge "the house of Eli for ever because of the iniquity, that he knew his sons were preparing a curse for themselves and did not prevent them." To judge on account of a crime, is the same as to punish it. עד־עולם, i.e., without the punishment being ever stopped or removed. להם מקללים, cursing themselves, i.e., bringing a curse upon themselves. "Therefore I have sworn to the house of Eli, that the iniquity of the house of Eli shall not (אם, a particle used in an oath, equivalent to assuredly not) be expiated by slain-offerings and meat-offerings (through any kind of sacrifice) for ever." The oath makes the sentence irrevocable. (On the facts themselves, see the commentary on 1-Samuel 2:27-36.)

In that day - In that time which I have appointed for this work, which was about twenty or thirty years after this threatning. So long space of repentance God allows to this wicked generation. When I begin, &c. - Tho' this vengeance shall be delayed for a season, to manifest my patience, and incite them to repentance; yet when once I begin to inflict, I shall not desist 'till I have made a full end.