This is also a matter of interpretation.
When reading the book of Revelation it states:
Rev 21:23 And
the city had no need of the sun, neither of the moon,
to shine in it: for the glory of God did lighten it, and the Lamb
is the light thereof.
Rev 22:5 And there shall be
no night there; and they need no candle,
neither light of the sun; for the Lord God giveth them light: and they shall reign for ever and ever.
Rev 22:14 Blessed
are they that do his commandments, that they may have right to the tree of life,
and may enter in through the gates into the city.
Rev 22:15 For without are dogs, and sorcerers, and whoremongers, and murderers, and idolaters, and whosoever loveth and maketh a lie.
The Bible says God created the sun and moon for a purpose:
Gen 1:14 And God said, Let there be lights in the firmament of the heaven
to divide the day from the night; and let them be for signs, and for seasons, and for days, and years:
Gen 1:15 And let them be for lights in the firmament of the heaven to give light upon the earth: and it was so.
Gen 1:16 And God made two great lights;
the greater light to rule the day, and the lesser light to rule the night:
he made the stars also.
Gen 1:17 And God set them in the firmament of the heaven to give light upon the earth,
Gen 1:18 And
to rule over the day and over the night, and to divide the light from the darkness: and God saw that
it was good.
In the book of Revelation above, there is no "time" .
Time was created for those who still remained outside the city.
The day and the night respresent the children of God/good and the children of the devil/evil.
The sun and the moon represent the role of the Father and the Mother and the generations to come are the stars.
1Th 5:5 Ye are all the children of light, and the children of the day: we are not of the night, nor of darkness.
Psa 72:5 They shall fear thee as long as the sun and moon endure, throughout all generations.
Eph 6:4 And,
ye fathers, provoke not your children to wrath: but bring them up in the nurture and admonition of the Lord.
Col 3:21 Fathers, provoke not your children
to anger, lest they be discouraged.
The best interpretation the bible gives itself is in the case of Joseph:
Gen 37:9 And he dreamed yet another dream, and told it his brethren, and said, Behold, I have dreamed a dream more; and, behold,
the sun and the moon and the eleven stars made obeisance to me.
Gen 37:10 And he told
it to his father, and to his brethren: and his father rebuked him, and said unto him, What
is this dream that thou hast dreamed?
Shall I and thy mother and thy brethren indeed come to bow down ourselves to thee to the earth?
Gen 37:11 And his brethren envied him; but his father observed the saying.
And God created man from the 'dust' of the earth.
Gen 13:16 And I will make thy seed as the dust of the earth: so that if a man can number the dust of the earth,
then shall thy seed also be numbered.
When Jesus came to earth there wasn't much faith left to be found.
I believe this "dust" represents the lost.
And from among the dust God created a man in his own image and likeness by breathing into him the breath of life.
Life is the knowledge of God.
From Adam who is the physical father of us all, God took a woman, who is the mother of us all.
These two are the Sun and the Moon.
Why day 4?
I believe 1-3 are days of restoration.
But during those 3 days the world is lying in darkness.
Hos 6:1 Come, and let us return unto the LORD: for he hath torn, and he will heal us; he hath smitten, and he will bind us up.
Hos 6:2 After two days will he revive us: in the third day he will raise us up, and we shall live in his sight.
Hos 6:3 Then shall we know,
if we follow on to know the LORD: his going forth is prepared as the morning; and he shall come unto us as the rain, as the latter
and former rain unto the earth.
And the evening and the morning was the 4th day.
Mat 18:10 Take heed that ye despise not one of these little ones; for I say unto you, That in heaven their angels do always behold the face of my Father which is in heaven.
Mat 18:11 For the Son of man is come to save that which was lost.
Mat 18:12 How think ye? if a man have an hundred sheep, and one of them be gone astray, doth he not leave the ninety and nine, and goeth into the mountains, and seeketh that which is gone astray?
Mat 18:13 And if so be that he find it, verily I say unto you, he rejoiceth more of that
sheep, than of the ninety and nine which went not astray.
Mat 18:14 Even so it is not the will of your Father which is in heaven, that one of these little ones should perish.
I don't know if man can even come close to full capacity of Mercy God has towards us.
Will there be punishment? Yes, this is righteous judgment and those who do wrong will pay a price.
If all people that are evil yet remain outside the city, what are they there for?
Does God have a plan for them as well?
I believe so.
And so history goes round and round, world without end.
This is simply my interpretation and subject to change as new evidence and data become availabe

Hugs