Two Ways in Which a Man is Called - Martin Luther

"No man should undertake anything, except he be called thereunto.
Calling is two-fold; either divine, which is done by the highest power, which is of faith; or else it is a calling of love, which is done by one's equal, as when one is deried by one's friend to preach a sermon.
Both vocations are necessary to secure the conscience."

Martin Luther (Table-Talk CCCXCII)