Is expiation incumbent upon someone who swore not to lend money to a person and then retracted his oath? And what is the expiation?

If you made an oath intentionally, it is binding, and you are obligated to offer expiation for the oath, even if you were angry, unless the anger reached a point of unconsciousness. If you regret it and deem retraction better, then retract and offer expiation. However, if the oath was uttered unintentionally, without heartfelt intent, it is a vain oath (yamin (definition) laghw), non-binding, and requires no expiation. The details of the oath's expiation are mentioned in the verse: {Allah will not impose blame upon you for what is unintentional in your oaths, but He will impose blame upon you for what you intended of oaths. So its expiation is the feeding of ten needy people from the average of that which you feed your [own] families or clothing them or freeing a slave. But whoever finds not [the means] - then a fast of three days. That is the expiation for oaths when you have sworn. And guard your oaths. Thus does Allah make clear to you His verses that you may be grateful.}.