In "Thank You, M'am," what does Mrs. Jones mean when she says "shoes got by devilish ways will burn your feet"?

I think that one of the most profound elements of the
story is how Mrs. Jones achieves a quality of transcendence.  She is clearly of this
world, as is Roger.  Yet, she speaks with an authority and a stature that is almost
omnipresent, part of the reason why Roger cowers in her presence.  She speaks from a
position of experience and almost with an unquestioned authority from a moral and social
point of view.  When Mrs. Jones speaks about "shoes got by the devil" it is a statement
about how Roger can seize this moment to change his ways and refrain from engaging in
behavior that is spiritually destructive and not socially redeeming.  Mrs. Jones
furthers this with the idea of how she, herself, has "done things" that reflect a
succumbing to temptation.  Hughes leaves it at that, not engaging in any more, but
developing in both Roger and the reader the idea that Mrs. Jones' experience should not
be questioned, but rather respected and understood.  Her warning to Roger and then her
giving him the money that he so coveted is a spiritual warning to Roger, an instant
where epiphany presents itself for the hope of profound and lasting personal
change.