Moroni Chapter 7 is the text of a sermon preached by Mormon and covers a wide range of important topics. As touching angels, Mormon does not relate an account of any particular visitation.  Instead he talks about the conditions under which angels minister to men.

In the first place, he makes the statement that angels have ministered unto men leading up to the mortal ministry of Christ in order to inform them of what they could look forward to in his mission.  He then transitions and asks whether angels still ministered unto men after the coming of Christ.  His answer is a resounding yes, and he states in verse 30 that angels show “themselves unto them of strong faith and a firm mind in every form of godliness.”  This is a high, but achievable, standard.

Mormon then goes on to explain that a failure on our part (generally) to be in receipt of the ministering aid of angels would be a grave indictment against us.  You see, if the ministering of angels has ceased, then our faith has ceased also, “and awful is the state of man, for they are as though there had been no redemption made.” These are undeniably harsh words.