This is how God inspired me, Brother Francis, to embark upon a life of penance. When I was in sin, the sight of lepers nauseated me beyond measure; but then God himself led me into their company, and I had pity on them. When I had once become acquainted with them, what had previously nauseated me became a source of spiritual and physical consolation for me. After that I did not wait long before leaving the world.
First Paragraph of the Testament of St. Francis

St. Francis and leper