'Ministers' in the Bible

who has also made us competent, as ministers of the new covenant; not of letter, but of spirit. For the letter kills, but the Spirit quickens.

but in everything commending ourselves as God's ministers, in much endurance, in afflictions, in necessities, in straits,

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

Are they ministers of Christ? (I speak as being beside myself) I above measure so; in labours exceedingly abundant, in stripes to excess, in prisons exceedingly abundant, in deaths oft.