Allah, the Exalted, informs that when the people of the earth were all drowned, except for the people on the ship, He commanded the earth to swallow its water, which had sprang from it and gathered upon it. Then He commanded the sky to cease raining.
(And the water was made to subside) This means that it (the water) began to decrease.
(and the decree was fulfilled.) This means that all of those who disbelieved in Allah were removed from the people of the earth. Not a single one of them remained upon the earth.
(And it (the ship) rested) This is referring to the ship and those who were in it.
(on (Mount) Judi.) Mujahid said, "Judi is a mountain in Al-Jazirah (Northwest Mesopotamia) where the mountains sought to tower above each other on the day of the drowning. On that day of destruction, all the mountains sought to be higher (to avoid being overcome by the water). However, this mountain (Judi) humbled itself for Allah, the Mighty and Sublime, and therefore it was not drowned. This is why Nuh's ship anchored upon it." Qatadah said, "The ship rested upon it (Mount Judi) for a month before they (the people) came down from it. " Qatadah also said, "Allah made Nuh's ship remain on Mount Judi in the land of Al-Jazirah, as a lesson and a sign." Even the early generations of this Ummah saw it. How many ships are there that have come after it and have been destroyed and became dust
(and it was said: "Away with the people who are wrongdoing!") means destruction and loss for them. The term "away with" here implies being far away from the mercy of Allah. For verily, they were destroyed to the last of them, and none of them survived.