King James Version
10 In the third year of Cyrus king of Persia
a thing was revealed unto Daniel,
whose name was called Belteshazzar;
and the thing was true,
but the time appointed was long:
and he understood the thing,
and had understanding of the vision.
2 In those days I Daniel was mourning three full weeks.
3 I ate no pleasant bread,
neither came flesh nor wine in my mouth,
neither did I anoint myself at all,
till three whole weeks were fulfilled.
This is an amazing account in the Bible.
Involving a prophet, a king, two powerful angels (one of which was a chief prince), and two enemy princes.
Prophet Daniel was given the vision, as he was fasting.
King James Version
4 And in the four and twentieth day of the first month,
as I was by the side of the great river, which is Hiddekel;
5 Then I lifted up mine eyes, and looked,
and behold a certain man clothed in linen,
whose loins were girded with fine gold of Uphaz:
6 His body also was like the beryl,
and his face as the appearance of lightning,
and his eyes as lamps of fire,
and his arms and his feet like in colour to polished brass,
and the voice of his words like the voice of a multitude.
7 And I Daniel alone saw the vision:
for the men that were with me saw not the vision;
but a great quaking fell upon them,
so that they fled to hide themselves.
8 Therefore I was left alone,
and saw this great vision,
and there remained no strength in me:
for my comeliness was turned in me into corruption,
and I retained no strength.
9 Yet heard I the voice of his words:
and when I heard the voice of his words,
then was I in a deep sleep on my face,
and my face toward the ground.
10 And, behold,
an hand touched me,
which set me upon my knees
and upon the palms of my hands.
11 And he said unto me,
a man greatly beloved,
understand the words that I speak unto thee,
and stand upright:
for unto thee am I now sent.
And when he had spoken this word unto me,
I stood trembling.
12 Then said he unto me,
Fear not, Daniel:
for from the first day
that thou didst set thine heart to understand,
and to chasten thyself before thy God,
thy words were heard,
and I am come for thy words.
13 But the prince of the kingdom of Persia
withstood me one and twenty days:
but, lo, Michael,
one of the chief princes,
came to help me;
and I remained there with the kings of Persia.
14 Now I am come to make thee understand
what shall befall thy people in the latter days:
for yet the vision is for many days.
15 And when he had spoken such words unto me,
I set my face toward the ground,
and I became dumb.
16 And, behold,
one like the similitude of the sons of men touched my lips:
then I opened my mouth,
and said unto him that stood before me,
O my lord,
by the vision my sorrows are turned upon me,
and I have retained no strength.
17 For how can the servant of this my lord
talk with this my lord?
for as for me,
straightway there remained no strength in me,
neither is there breath left in me.
Weakened by the fast, Daniel is given strength:
King James Version
18 Then there came again and touched me
one like the appearance of a man,
and he strengthened me,
19 And said,
O man greatly beloved,
peace be unto thee,
yea, be strong.
And when he had spoken unto me,
I was strengthened,
Let my lord speak;
for thou hast strengthened me.
20 Then said he,
Knowest thou wherefore I come unto thee?
and now will I return to fight with the prince of Persia:
and when I am gone forth,
lo, the prince of Grecia shall come.
21 But I will shew thee
that which is noted in the scripture of truth:
and there is none that holdeth with me in these things,
but Michael your prince.
Daniel had no idea, that while he was fasting, a spiritual battle was raging in the angelic realm, involving two angels, and the prince of Persia.
After which the prince of Grecia would join, too.
The prince of Persia wanted to stop the angel from delivering GOD's message to Daniel.
The battle was such, that it took the angel 21 days to get to Daniel.
But the messenger had to return and fight the battle.
The angel assigned to Israel, angel Michael -- "one of the chief princes" -- helped this angel.
Many would argue that Daniel "saw" and "imagined" things, from hunger.
But a born again would counter with the fact that this is the Bible we're talking about.
A fast was needed, that Daniel may witness the vision GOD wanted him to see.
We are to be pure before the LORD.