'Ministers' in the Bible

who also made us sufficient as ministers of a new covenant; not of the letter, but of the spirit: for the letter killeth, but the spirit giveth life.

but in everything commending ourselves, as ministers of God, in much patience, in afflictions, in necessities, in distresses,

It is no great thing therefore if his ministers also fashion themselves as ministers of righteousness, whose end shall be according to their works.

Are they ministers of Christ? (I speak as one beside himself) I more; in labors more abundantly, in prisons more abundantly, in stripes above measure, in deaths oft.