Noach was a righteous man, with good deeds, the main generations of the righteous. He was perfect in his generations who walked in the ways of Hashem who encouraged him, unlike Avraham who would strengthened himself in his righteousness. If Noach would have lived in the Generation of Avraham in some ways he would have been more righteous but in other ways he would not have been considered of any importance. Noach had three sons; Shem, Cham, and Yafes.
The world became corrupted with immorality idolatry and full of robbery. These were all caused by their opposition to the Tzadikim of their generation; Mesushelach and Noach, and not receiving their oral teaching of Holiness leading them to twist all the teachings. Hashem saw the corruption and how all creatures including cattle, beasts and birds had corrupted their ways by mating with members of other species.
Hashem told Noach that he plans on destroying all life on the world due to their immorality and idolatry which brings death to the world, killing both good and bad. Despite this their final verdict was sealed only because of mass robbery. Even the earth would be destroyed, blotted out and obliterated to the depth of a plowshare, 3 Tefachim, roughly a foot (27 cm).
Instruction of Ark
Hashem told Noach to make for himself an ark of gopher wood, which sounds like gophris - sulphur which they were decreed to be destroyed with. He should make the ark with compartments which would serve as dwelling places for the domestic animals and wild beasts. He was to caulk it both inside and outside with pitch, due to the strength of the water. Moshe's ark which was in calm waters was coated with clay inside and pitch only on the outside. Also so the righteous Moshe should not smell the bad odor of pitch.
Noach was to size it: 300 cubits long, 50 cubits wide and 30 cubits high. He was to make a window which would server as a skylight for the ark as well as a precious stone, which would generate light.
Its roof should slant upwards narrowing to the width of one cubit which was flat and was not pointed to the end, so the waters should run down. It should have a door on its side, so that the rain should not enter it. It would have three stories one above the other, a bottom for garbage, second story for animal dwelling, and an upper third story for the people.
Although Hashem had many ways to save Noach, he did so through the ark, giving his generation a chance to repent as they inquired about Noach working on it for 120 years and replied that Hashem planed on bringing a flood to the world.
Hashem announced that He is bringing a flood of water upon the earth, to destroy all flesh in which there is the spirit of life, from beneath the heavens. Hashem was now ready to agree to the angels who urged Him long ago not to create man. All that is upon the earth would perish. This flood would wear everything out, mix everything up and move everything from high ground to low ground and floated everything down to Bavel which is deep, it was therefore called a בלה, בלבל, הוביל - מבול.
Hashem will uphold His covenant with Noach that the fruits will not rot and become moldy and that he should not be killed by the wicked of his generation. Noach is to enter the ark with his sons, wife and daughter-in-laws, they are prohibited to have marital relations.
Noach is to bring with him into the ark at least two of each living thing, of all flesh, to preserve their life. These should include one male and one female. This included even demons. Two from each kind of bird, animal and ground creeper, that did not have relations with other species and corrupts their way, will come on their own to Noach so he could preserve their life. Those that whom the ark let them enter and did not reject, were to be saved.
Noach is to take for himself and gather every food that is eaten and it should be for him and them to eat. Noach did according to all that Hashem had commanded him, specifically the building of the ark.
Entering the Ark
Hashem told Noach to enter the ark along with his household for he has found him a righteous man in his generation. This praise was in front of Noach, therefore Hashem did not call him a 'perfectly righteous man' since we tell only partial praise in a person’s presence and all of it in his absence. 
From all the clean animals Noach should take seven pairs of husband and wife. From the animals that are not clean, Noach should only take two, a single husband and wife. Since Noach studied Torah he knew which animals were going to distained to be pure for the Jewish Nation. More kosher animal were taken, so Noach could offer sacrifices from them upon leaving the ark. Also, from the clean birds of the skies, Noach was to take seven pairs, male and female, to keep their seed alive on the face of the earth.
Hashem declared that in another seven days, He will make it rain upon the earth for forty days and forty nights, and He will blot out all beings that He created off the face of the earth. Hashem took into consideration the honor of the tzadik Mesushelach who had passed away when Noach turned 600 and delayed the the retribution for the seven days of his mourning.
Permitting of Meat
They were now permitted to eat animal meat which had not been allowed until then, just like they had been permitted to eat vegetation at the time of Adom.
- ^ a b c d e Rashi Berashis 6:9
- ^ a b c Shover Zadim Parshas Noach
- ^ a b c Rashi Berashis 6:11
- ^ a b c Likutay Halachos, Hilchos Reshis Hagaz 5
- ^ Rashi Berashis 6:12
- ^ a b c Rashi Berashis 6:13
- ^ a b c d e f Rashi Berashis 6:14
- ^ a b c d e f Rashi Berashis 6:16
- ^ a b c Rashi Berashis 6:17
- ^ a b c Rashi Berashis 6:18
- ^ a b c Rashi Berashis 6:19
- ^ a b c Rashi Berashis 6:20
- ^ Rashi Berashis 6:22
- ^ Rashi Berashis 2:1
- ^ a b Rashi Berashis 2:2
- ^ Rashi Berashis 2:3
- ^ Rashi Berashis 2:4
- ^ Rashi Berashis 30