John Chrysostom
See how he also directs them imperceptibly toward the same thing by what follows. To what he has said he adds: "your abundance should supply their lack" (v. 14).
By these words, as by those above, he wants to make his commandment easier. Not only by this, but also by presenting a reward, he makes it easier and speaks of them as worth more than they are.
"Their abundance should supply your lack, so that there may be equality." What does he mean? "You are rich in money, and they in purity of life and boldness before God. Therefore give them from your possessions, which you have in abundance and they lack, so that you yourselves may receive from them, in return, boldness before God. In this they are rich, and you feel your lack."
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Do you see now how he imperceptibly persuades the Corinthians to give both beyond strength and from lack? "If you wish," he says, "to receive only from abundance, then give from abundance. But if you wish to acquire everything, then give also from lack and beyond strength."
Yet he does not say this openly, but leaves the hearers to reach it by their own conclusion. Meanwhile he continues the exhortation that was proposed and suited to his purpose, adding what apparently ought to be said: "so that there may be equality."
How will this equality exist? In this way: "we and they will mutually share our abundance with one another and supply lacks." But what equality is there in paying spiritual things for bodily things? The latter far surpasses the former.
Why, then, does he call this equality? He called it equality only with regard either to abundance and lack, or to the present life. Therefore, after saying "equality," he added, "at the present time."
He said this in order to cast down the pride of the rich and show that, after departing from here, those who have lived spiritually will have a greater advantage. In the present life we are in many respects of equal honor. But then a great separation will occur, and the greatest advantages will appear, because the righteous will shine brighter than the sun.
Then, since he has shown that the Corinthians not only give, but also receive something greater in return, he wants to stir their zeal in another way. He shows that if they do not share their goods with others, they will have no more for themselves, even if they take everything.
He brings forward an ancient account as an example: "as it is written, 'He who gathered much had nothing over, and he who gathered little had no lack'" (v. 15; Ex 16:18).
So it was in the gathering of the manna. Some gathered more, others less, but both found they had the same measure. By this God punished greed. The Apostle pointed to this both to alarm the Corinthians by the ancient event and to persuade them never to desire more, nor to grieve if they have little.