Angels are subject unto him, to minister
according to the word of his command,
showing themselves unto them of strong faith
and a firm mind in every form of godliness.
And the office of their ministry
is to call men unto repentance,
and to fulfil and to do the work
of the covenants of the Father,
which he hath made unto the children of men,
to prepare the way among the children of men,
by declaring the word of Christ
unto the chosen vessels of the Lord,
that they may bear testimony of him.
And by so doing,
the Lord God prepareth the way
that the residue of men may have faith in Christ,
that the Holy Ghost may have place in their hearts,
according to the power thereof;
and after this manner bringeth to pass the Father,
the covenants which he hath made
unto the children of men.
(Moroni 7:30-32)