Daniel 8:16-21
Daniel 8:16
And I heard a man's voice between the banks of Ulai, which called, and said, Gabriel, make this man to understand the vision.
We are not told who the man’s voice was that spoke to Gabriel to give Daniel the understanding of the vision.  It may have been the Lord himself commanding Gabriel to speak with Daniel as Daniel is still in vision mode.
Daniel 8:17
So he came near where I stood: and when he came, I was afraid, and fell upon my face: but he said unto me, Understand, O son of man: for at the time of the end shall be the vision.
Gabriel must have had a tremendous look about him since Daniel fell on his face in fear of him.  Gabriel then began to reveal to Daniel that the vision was set for the time of the end.  Based upon Daniel 9, this is probably speaking about the end of the Old Testament dispensation of law and the coming of the long awaited Messiah.  Daniel is called “son of man” as a representative of the human race in contrast to the angelic beings he was speaking with.
Daniel 8:18
Now as he was speaking with me, I was in a deep sleep on my face toward the ground: but he touched me, and set me upright.
At the moment Daniel had fallen into a very deep sleep, something almost like a coma and he was on the ground.  He must have fallen in this sleep right after he saw Gabriel and fell on the ground in fear of him.  It was like he passed out in fear.  So Gabriel touched him, woke him, and then sat him upright to give him the explanation of the vision.
Daniel 8:19
And he said, Behold, I will make thee know what shall be in the last end of the indignation: for at the time appointed the end shall be.
The vision is describing events which will happen in the Persian and Greek periods, Gabriel is now pointing Daniel to the end times.  He is speaking not about the end times concerning the second coming of Christ but the end times which will commence after the first coming of Christ.  The last end of the indignation will be when Rome conquers Judah and will occupy it.  Here we read that the end is appointed and doesn’t just happen.  As we saw in the symbolic number of the 2300 days denoting a time of beginning and a time of end.  The word “indignation” carries with it the meaning of “rage or anger.”  That final anger of God with Israel will come in 70 A.D. when Rome destroys Judah and Jerusalem.
Daniel 8:20
The ram which thou sawest having two horns are the kings of Media and Persia.
He is reiterating the meaning of the vision. As you recall the two horns were Media and Persia.  The bigger horn belonged to Persia as it overcame the Medes by the power of Cyrus.
Daniel 8:21
And the rough goat is the king of Grecia: and the great horn that is between his eyes is the first king.
Then Gabriel tells Daniel that the rough goat is the king of Greece and that great horn had represented Alexander the Great.