Why did Paul take support from Macedonia instead of from Corinth?
Paul took support from the poor believers in Macedonia so he would not have to accept any money from Corinth, which was a wealthy commercial city. He chose to preach the gospel to the Corinthians freely, taking wages from other churches to serve them rather than burden them.
Les explains that Paul, perhaps against his better judgment, accepted offerings from the poor believers in Macedonia. Greece was mountainous, with little means of making a living or growing crops, so that area was poor and destitute. Yet Paul took money from there so that he would not have to take a dime from Corinth, a wealthy, commercial city. In 2 Corinthians he says he preached the gospel of God freely and took wages from other churches to do the Corinthians service, not wanting to burden them.
I robbed other churches, taking wages of them, to do you service.
And when I was present with you, and wanted, I was chargeable to no man: for that which was lacking to me the brethren which came from Macedonia supplied: and in all things I have kept myself from being burdensome unto you, and so will I keep myself.