Paul uses the image of a farmer sowing seeds to describe the results of giving. As a farmer's harvest is based on how much he sows, so will God's blessings be little or much based on how generously the Corinthians give. (See: [[rc://en/ta/man/translate/figs-metaphor]])
Here the word "heart" refers to the thoughts and emotions. AT: "give as he has determined" (See: [[rc://en/ta/man/translate/figs-metonymy]])
# not reluctantly or under compulsion
This can be translated with verbal phrases. AT: "not because he feels guilty or because someone is compelling him" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])