Because the Macedonians were offering more than they could afford, Paul was inclined to refuse their contribution, fearing that hardship would later cause them to reconsider their good deed. But because they showed themselves to be of such character that they stood firm, with a pure mind in the confidence of faith, attaching more importance to the promises for the future than to immediate rewards in the present, in the end it seemed right for him to accept their contribution.
Not only did the Macedonians give voluntarily, they insisted that Paul take what they had to offer. Their actions prove just how much they desired spiritual gifts.
"With much intreaty." Lo! Yet a third and a fourth. "Praying us." Lo! even a fifth. And when they were in affliction and in poverty. Here are a sixth and seventh. And they gave with excessiveness. Then since this is what he most of all wishes to provide for in the Corinthians' case, namely, the giving deliberately, he dwells especially upon it, saying, "with much intreaty," and "praying us." 'We prayed not them, but they us.' Pray us what? "That the grace and the fellowship in the ministering to the saints." Do you see how he again exalts the deed, calling it by venerable names. For since they were ambitious of spiritual gifts , he calls it by the name grace that they might eagerly pursue it; and again by that of "fellowship," that they might learn that they receive, not give only. 'This therefore they intreated us,' he says, 'that we would take upon us such a ministry.'
[AD 384] Ambrosiaster on 2 Corinthians 8:4