2 Corinthians 8:11

Now therefore perform the doing of it
This is a conclusion from the former advice, to finish what was readily willed; for as it is not enough to do a thing, unless it is done cheerfully and willingly, so it is not sufficient to express a good will to such service as is here called to, without doing it; both should go together:

that as there was a readiness to will, so there may be a performance
also;
in some cases there is neither power nor will to do good; in others there is will, when there is not a power; but in this case of beneficence to the poor saints, as there was a willingness declared, there was an ability in the Corinthians to perform; they had it in the power of their hands, more or less, to act: and the apostle in the last clause of this verse points out the rule and measure of their liberality,

out of that which you have;
according to your abilities, and as God has prospered you; and with which he shuts up the mouths of all objectors, rich and poor: should the rich say, would you have us give away all we have? the answer is, no; but "out of that which you have", something of it, according as you are able; should the poorer sort say, we are in mean circumstances, we have families to provide for, and can spare little, and what we can do is so trifling, that it is not worth giving or accepting; the reply is, give "out of that which you have", be it less or more; it follows,