Arthur helped him up, saying, "There is no need for this. When I decided to help you, I wasn't hoping for you to swear your life to me."
He really didn't care that the man was swearing to repay the favor because he wasn't going to count on his promise. What he relied on was the Fate Binding divine ability.
As long as he helped the man, he would receive significant feedback from the man whenever the man makes progress in his cultivation in the future. So he didn't really care about any verbal promise of gratitude.
He gave the man a rank 4 cultivation technique that could help him advance to the fourth mortal coil. This was a cultivation technique that he gained from raiding the Milton family together with Storm Hawk.
Storm Hawk and his other partners in crime also have a copy of this technique. They had shared it because it would be wasteful not to.
