Respuesta :
I think its more like when you are applying for a job. If you are going into an interview (even if its just for mcdonalds) you would want to dress nicely to give a good impression.
In this saying, dress is used as meaning working harder than you’ve already worked and implementing new set of ideals. Then, when you dress for the position you have, then you are content and with no willing of going further. If there is a position you want but do not have, you should make an effort to dress for it and reach it.