Adam Clarke Bible Commentary
Herein I give my advice - For I speak not by way of commandment, Co2 8:8.
For this is expedient for you - It is necessary you should do this to preserve a consistency of conduct; for ye began this work a year ago, and it is necessary that ye should complete it as soon as possible.
Not only to do, but also to be forward - Το ποιησαι - και το θελειν, literally, to do and to will; but as the will must be before the deed, θελειν, must be taken here in the sense of delight, as it frequently means in the Old and New Testaments. See several examples in Whitby.
Some MSS. transpose the words: allowing this, there is no difficulty.
A year ago - Απο περυσι. It was about a year before this that the apostle, in his first epistle, Co1 16:2, had exhorted them to make this contribution and there is no doubt that they, in obedience to his directions, had begun to lay up in store for this charitable purpose; he therefore wishes them to complete this good work, and thus show that they were not led to it by the example of the Macedonians, seeing they themselves had been first movers in this business.
Jamieson-Fausset-Brown Bible Commentary
advice--Herein he does not (as some misinterpret the passage) disclaim inspiration for the advice he gives; but under the Spirit, states that it is his "opinion" [ALFORD] or "judgment" [ELLICOTT, and others], not a command, that so their offering might be free and spontaneous.
this--my giving you an advice, not a command.
who have begun before--"seeing that ye have begun before" the Macedonian churches; "a year ago" should be connected with this clause.
not only to do, but also to be forward--There were three steps: (1) the forwardness, more literally, "the will"; (2) the setting about it, literally, "doing it"; (3) completion of it [ALFORD]. In the two former, not only the act, but the intention, the Corinthians preceded the Macedonians. BENGEL explains, "Not only to do" FOR THE PAST YEAR, "but also to be forward" or willing FOR THIS YEAR. ELLICOTT translates, "already," instead of "before": "Ye began already a year ago, not only to do, but also to be forward." It appears hence, that something had been done in the matter a year before; other texts, however, show the collection was not yet paid (compare Co2 8:11 and Co2 9:5, Co2 9:7). This agrees with one, and only one supposition, namely, that every man had laid by in store the fund from which he was afterwards to contribute, the very case which is shown by Co1 16:2 to have existed [PALEY, HorÃ&brvbr PaulinÃ&brvbr].
John Gill Bible Commentary
And herein I give my advice,.... As Daniel did to Nebuchadnezzar, Dan 4:27. The apostle did not choose to make use of his apostolical authority, or give orders, as he sometimes did in such cases; he did not think fit to speak by way of commandment, obliging them to what they ought to do willingly; looking upon this the most prudential step, and wisest method he could take in order to succeed, only to give his judgment in this matter, as what would be best for them, and most conducive to their real good:
for this is expedient for you; most versions read it, "profitable"; doing acts of beneficence is profitable to persons, as to things temporal, God usually blessing such with a greater affluence of the things of life, and which indeed is often promised; and is also profitable with respect to things spiritual, for if God does not make it up to them in temporal enjoyments, yet with his presence, the discoveries of his love, the joys of his salvation, and an increase of every grace; so Gaius, that hospitable man to the apostle, and all Christian strangers, was in much spiritual health, and a prosperous condition in his soul, when but in an ill state with respect to his body: yea, such a conduct is profitable in relation to things eternal; for as it springs from the grace of God, and men are assisted therein by it, and is exercised towards persons that have received it, it will be rewarded with a reward of grace; though it may be, the apostle here does not so much argue from the utility, as the decency of it in the Corinthians;
who, says he,
have began before, a year ago, not only to do, but also to be forward, or "willing": it is hard to say whether the apostle designs to commend or reprove them; and indeed, it seems as if there was a mixture of praise and dispraise in this passage; it was in their favour that they had begun before, even a year ago, and were willing and forward of themselves to this good work; yea, were the first that set it on foot, and so were an example to the Macedonian churches, and others; but then this was against them, that the other churches, which began later than they, had finished before them; whether this their charity was obstructed, as some have thought, through some affliction and persecution that befell them, which if it appeared would much excuse them; or rather it was neglected through lukewarmness and indolence; wherefore the apostle gives his sentiments, that to save their own credit, it was expedient for them to finish what they had begun; for otherwise, as their boasting of them would be in vain, so they would expose themselves to contempt and incur disgrace; and it was not only proper that they should do this, but do it willingly, and with much cheerfulness, for that is meant by being "forward" or "willing"; that they not only do it, but do it with a good will, which they at first discovered.