What did Jonathan Edwards have to say about the fact that he owned slaves?

I recently learned from a John Piper podcast that Jonathan Edwards owned slaves . Edwards lived in the early and mid 18th century, long before the American Civil War, and passed away decades before Wilberforce would begin his abolitionist work in England.* Nevertheless, many believe that ownership of slaves seemed uncharacteristic of a man like Edwards who, in his preaching and writing, placed such an emphasis on piety and holiness. **What did Edwards have to say about his ownership of slaves? Did he ever address the issue of slavery in any of his published works?** --- \* Of course, that's simply context, and not an excuse.