'Messengers' in the Bible

for I think that God did set forth us the apostles last -- as appointed to death, because a spectacle we became to the world, and messengers, and men;

have ye not known that we shall judge messengers? why not then the things of life?

because of this the woman ought to have a token of authority upon the head, because of the messengers;

If with the tongues of men and of messengers I speak, and have not love, I have become brass sounding, or a cymbal tinkling;