G-d could have created everything in an instant.
Psa 33:6-9 (KJV) By the word of the LORD were the heavens made; and all the host of them by the breath of his mouth. 7 He gathereth the waters of the sea together as an heap: he layeth up the depth in storehouses. 8 Let all the earth fear the LORD: let all the inhabitants of the world stand in awe of him. 9 For he spake, and it was done; he commanded, and it stood fast.
But He created the Heavens and the Earth in six days.
Exo 20:11 (KJV) For in six days the LORD made heaven and earth, the sea, and all that in them is, and rested the seventh day: wherefore the LORD blessed the sabbath day, and hallowed it.
Day 1 - The beginning of creation
Gen 1:1 (KJV) In the beginning God created the heaven and the earth.
Day 4 - The sun, a picture of Messiah
Gen 1:15-16 (KJV) And let them be for lights in the firmament of the heaven to give light upon the earth: and it was so. 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.
Mal 4:2 (KJV) But unto you that fear my name shall the Sun of righteousness arise with healing in his wings;.
Day 6 - Man
Gen 1:27 (KJV) So God created man in his own image, in the image of God created he him; male and female created he them.
Day 7 - Sabbath was made holy, or separated (kadosh): a picture of the Messianic Kingdom
Gen 2:2 (KJV) And on the seventh day God ended his work which he had made; and he rested on the seventh day from all his work which he had made. 3 And God blessed the seventh day, and sanctified it: because that in it he had rested from all his work which God created and made.
Psa 90:4 (KJV) For a thousand years in thy sight are but as yesterday when it is past, and as a watch in the night.
2 Pet 3:8-10 (KJV) But, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day. 9 The Lord is not slack concerning his promise, as some men count slackness; but is longsuffering to us-ward, not willing that any should perish, but that all should come to repentance. 10 But the day of the Lord will come as a thief in the night; in the which the heavens shall pass away with a great noise, and the elements shall melt with fervent heat, the earth also and the works that are therein shall be burned up.
Heb 4:4 For he spake in a certain place of the seventh day on this wise, And God did rest the seventh day from all his works. 5 And in this place again, If they shall enter into my rest. 6 Seeing therefore it remaineth that some must enter therein, and they to whom it was first preached entered not in because of unbelief: 7 Again, he limiteth a certain day, saying in David, To day, after so long a time; as it is said, To day if ye will hear his voice, harden not your hearts. 8 For if Joshua had given them rest, then would he not afterward have spoken of another day. 9 There remaineth therefore a rest to the people of God. 10 For he that is entered into his rest, he also hath ceased from his own works, as God did from his. 11 Let us labour therefore to enter into that rest, lest any man fall after the same example of unbelief.
1000 years = 1 day. 7 days = 7000 years from creation until the end of time
The Jewish Sages concluded that the creation week was a pattern of the history of the world
Talmud
R. Kattina said: Six thousand years shall the world exist, and one [thousand, the seventh], it shall be desolate, as it is written, And the Lord alone shall be exalted in that day. Abaye said: it will be desolate two [thousand], as it is said, After two days will he revive us: in the third day, he will raise us up, and we shall live in his sight.
It has been taught in accordance with R. Kattina: Just as the seventh year is one year of release in seven, so is the world: one thousand years out of seven shall be fallow, as it is written, And the Lord alone shall be exalted in that day, and it is further said, A Psalm and song for the Sabbath day, meaning the day that is altogether Sabbath and it is also said, For a thousand years in thy sight are but as yesterday when it is past.
The Tanna debe Eliyyahu teaches: The world is to exist six thousand years. In the first two thousand there was desolation; two thousand years the Torah flourished; and the next two thousand years is the Messianic era, but through our many iniquities all these years have been lost. (Sanhedrin 97a-b)
This idea is also found in extra-biblical writings during the period just prior to and after the birth of Yeshua
The Epistle of Barnabas
"And even in the beginning of the creation he makes mention of the sabbath. And God made in six days the works of his hands; and he finished them on the seventh day, and he rested the seventh day, and sanctified it. Consider, my children what that signifies, he finished in six days. The meaning of it is this; that in six thousand years the Lord God will bring all things to an end. For with him one day is a thousand years; as himself testifieth, saying, Behold this day shall be as a thousand years. Therefore, children, in six days, that is, in six thousand years, shall be accomplished. And what is that he saith, And he rested on the seventh day: he meanth this; that when his Son shall come, and abolish the season of the Wicked One, and Judge the ungodly; and shall change the sun and moon, and stars: then he shall gloriously rest in that seventh day (The Lost Books of the Bible, chp. 13:3-6, Bell Publishing Company, 1979 New York, p. 160-161)."
The Secrets of Enoch, Chapter 33
1And I appointed the eighth day also, that the eighth day should be the first-created after my work, and that the first seven revolve in the form of the seventh thousand, and that at the beginning of the eighth thousand there should be a time of not-counting, endless, with neither years nor months nor weeks nor days nor hours.