Mosiah 3:1 - 3:5

Mosiah 3:1 And again my brethren, I would call your attention, for I have somewhat more to speak unto you; for behold, I have things to tell you concerning that which is to come.

Now King Benjamin wants to tell them about future events.

Mosiah 3:2 And the things which I shall tell you are made known unto me by an angel from God. And he said unto me: Awake; and I awoke, and behold he stood before me.

What he's about to tell them was made know to him when he was awaken from his sleep in the night time.
[Many visions come in the night. I guess that when a person is awaken from sleep, his mind is fresh and not dwelling on the events of the day. They had been forgotten, at least while asleep, and are not a distraction so that a person can give full attention to the message of the heavenly messenger. I guess we have to include the shock of it as well.]

Mosiah 3:3 And he said unto me: Awake, and hear the words which I shall tell thee; for behold, I am come to declare unto you the glad tidings of great joy.

The heavenly messenger or angel says he has a message that will thrill him and his people.

Mosiah 3:4 For the Lord hath heard thy prayers, and hath judged of thy righteousness, and hath sent me to declare unto thee that thou mayest rejoice; and that thou mayest declare unto thy people, that they may also be filled with joy.

The Lord has heard King Benjamin’s prayers regarding his people or what should he say to his people the next day. What the angel wants him to preach the next day will fill him with as much joy as it will fill the people.

Mosiah 3:5 For behold, the time cometh, and is not far distant, that with power, the Lord Omnipotent who reigneth, who was, and is from all eternity to all eternity, shall come down from heaven among the children of men, and shall dwell in a tabernacle of clay, and shall go forth amongst men, working mighty miracles, such as healing the sick, raising the dead, causing the lame to walk, the blind to receive their sight, and the deaf to hear, and curing all manner of diseases.

King Benjamin is to tell the people of the coming of the Lord, himself, to the earth as a mortal. He will be born just like any other man and have a body. He will be among the people performing various miracles such as healing the sick, giving eyesight to the blind, hearing to the deaf, bring the dead back to life, and those who are lame being able to walk.