Saint Vincent de Paul began a work of charity for men and women, the latter being the Sisters of Charity. His spiritual doctrine and method of preaching is a subject well worth studying for all sincere Catholics. Saint Vincent de Paul had his little method of bringing about conversions: "First show the reasons for loving goodness and hating evil; second, show what virtue is; third, show how it is attained." This work lays all of this out for the use of the preacher and the edification of the faithful.