He lived in the 1700's, and during the French and Indian Wars, he felt led to make a journey visiting among the Indians. It was a dangerous time for him to do this. The day before he left, news had just come to town that a war party had killed and scalped a group of settlers living near Pittsburgh. When John Woolman went to visit the Indians, he didn't go there as a negotiator. He certainly didn't go to threaten the Indians, or bargain with them.
Humility means listening more than prescribing.
It means walking with people, rather than talking at them. Humility was something which Jesus didn't use as a technique. Humility was Jesus' way of life . He taught by telling stories, parables drawn from everyday life. He taught by giving examples, and by asking questions.