V.1 “Come in” (Gen. 8:16,16Go forth of the ark, thou, and thy wife, and thy sons, and thy sons' wives with thee. (Genesis 8:16) “go forth”). We have to come in (Matt. 11:2828Come unto me, all ye that labor and are heavy laden, and I will give you rest. (Matthew 11:28)) before we can go out (Mark 16:1515And he said unto them, Go ye into all the world, and preach the gospel to every creature. (Mark 16:15)). We must also separate from the world (Heb. 13:1313Let us go forth therefore unto him without the camp, bearing his reproach. (Hebrews 13:13); James 4:44Ye adulterers and adulteresses, know ye not that the friendship of the world is enmity with God? whosoever therefore will be a friend of the world is the enemy of God. (James 4:4)). Separation is not isolation. Mixing with the world (to socialize) spoils our testimony. But telling others about Christ keeps us healthy Christians.
V.2-5,8 The animals were in two classes — clean and unclean.
V.10 After closing the door, God waits once more, just in case there might be a turning to Him. Jesus was seen standing, waiting in case Israel would turn to Him, even after He had gone back to heaven (Acts 7:5656And said, Behold, I see the heavens opened, and the Son of man standing on the right hand of God. (Acts 7:56)). We believers are now in that period of time. The door is still open. God is waiting for the last ones to be saved before He acts. The coming of the Lord Jesus for us (believers) will be the end of the day of grace. The door will then be shut.
V.23 Judgment fell on every living person, animal and bird outside the ark. And so today, not one person who has ever heard the gospel of the grace of God will ever have a second chance after the Lord Jesus comes.