According to Vincent de Paul’s first biographer, Louis Abelly, Vincent prayed to have a temptation against faith transferred to him to free a doctor of theology who was originally suffering from it. The temptation continued for three or four years until Vincent resolved to serve poor persons. While many biographers have accepted this story, its truth is doubtful for many reasons besides those that follow. Vincent never spoke of having this temptation himself. He never would have prayed for a transfer of temptation without advice from his spiritual director, and this advice would not have been given. The temptation would have occurred during a year that he said was the happiest of his life. At the time that the temptation would have ended, Vincent was not serving the poor. Instead, he was reforming clergy, converting heretics, and serving the Gondi family. It is well documented that Vincent’s work with persons who were poor developed out of responses to unanticipated needs and events, not as a result of an astonishing conversion.
Poole, Stafford C.M. and Slawson, Douglas C.M.
"A New Look At An Old Temptation: Saint Vincent de Paul's Temptation Against Faith and Resolution to Serve the Poor,"
Vincentian Heritage Journal: Vol. 11
, Article 1.
Available at: http://via.library.depaul.edu/vhj/vol11/iss2/1