Why did Martin Luther reject the idea of the priesthood (sacerdotalism)?

It's famously know that *Martin Luther*, rejected the idea of a *sacerdotal priesthood*. Meaning *priests* and *bishops* having a certain *special grace*, *conferred* on them at *ordination* or *installation* (in case of the *bishop*), also known as *sacerdatioalism*. Luther instead concluded that all Christians are *equal* under *Baptism* (have the same grace). Even known he did not reject the idea of the *office* of a *minister*, a person among the faithful that *administer* the *sacraments*, *preaches* and *leads* the congregation in prayer. Instead option for what Protestants call today the *Priesthood of all believers*. On what *theological* or *Biblical* grounds did Luther reach this rejection of *sacerdatioalism*?