And herein I give my advice - Not undertaking to command them, or to prescribe how much they should give. Advice will go much further than commands on the subject of charities.
For this is expedient for you - (συμφέρει sumpherei). That is, this will be of advantage to you; it will be profitable; it will be becoming. The idea is, that they were bound by a regard to consistency and to their own welfare, to perform what they had purposed. It became them; it was proper, and was demanded; and there would have been manifest disadvantages if it had not been done.
Who have begun before - Who commenced the collection a year before; see 2 Corinthians 8:6. It had been commenced with fair prospects of success, but had been interrupted probably by the dissensions which arose in the church there.
Not only to do - Not merely to accomplish it as if by constraint, or as a matter of compulsion and drudgery.
But also to be forward - Margin, “Willing.” So the Greek τὸ θέλειν to thelein. They were voluntary in this, and they set about it with vigorous and determined zeal and courage. There was a resolute determination in the thing, and a willingness and heartiness in it which showed that they were actuated by Christian principle. Consistency, and their own reputation and advantage, now demanded that they should complete what they had begun.