Genesis 7:6-9 is a short account of the ark's final preparation. It is a short description of all the animals and Noah's household boarding the ark. A more descriptive account of this event is found in Genesis 7:13-15 and Genesis 7:16.
Now Noah was six hundred years old when the flood of water came upon the earth. (Genesis 7:6)To anyone living in the post-flood world, any lifespan over 100 years is significant. But for those who lived in the pre-flood world, living to the age of 600 was typical. In fact, many of the men listed in the genealogy in Genesis 5 lived well past 900 years (see Genealogy of Genesis 5).
When Noah was 600 years of age, his sons were right around the age of 100 (see Genesis 5:32, Genesis 11:10). That means Noah was about half a millennium older than his sons... now that is what you call a generation gap!
Then Noah and his sons and his wife and his sons' wives with him entered the ark because of the water of the flood. (Genesis 7:7)As will be clearly stated later in Genesis 7, Noah's household entered the ark on the very same day that the flood hit (Genesis 7:13). None of the wives who entered the ark are explicitly named in Scripture. However, some have claimed that Naamah, the sister of Tubal-cain, was the wife of Noah (see Genesis 4:22). This, however, is without plain Scriptural evidence.
Of clean animals and animals that are not clean and birds and everything that creeps on the ground, there went into the ark to Noah by twos, male and female, as God had commanded Noah.(Genesis 7:8-9)Noah did not search the planet looking for all the animals which entered the ark. Instead, all the animals came to him (see Genesis 6:20). The only animals which Noah might have had to gather himself were the clean animals which God commanded him to bring in Genesis 7:1. Once the ark was fully loaded, God shut the door of the ark (Genesis 7:16). The rain was about to come. And it was about to come hard.
7 More Days - Genesis 7:4-5
How Did Noah Know Which Animals Were Clean? (Part 1) - Genesis 7:2-3
Noah's Obedience - Genesis 6:22
State Of The World (2469 BC): 120 Years Before The Flood - Genesis 6:3