You know a really great book is ambrose's book on the office of the priesthood. (A great work. It amazes me how you read the church fathers and how their advice works today, with a few cultural exceptions, and time based issues. Priests would be better served by studying patristics.)
"True it is, my son, that thou desirest the priesthood, that thou desirest a good work. Sublime is the dignity to which thou aspirest; but take care, for great also is the ruin to which this lofty dignity exposes thee.
Wherefore, no matter how vehemently thou mayest be attracted towards this holy state, do not presume to take to thyself the honor unless thou be called by me as Aaron was.
Not anyone, not even the apostles have chosen Me, but I have chosen them and have appointed then that they …[Altro]