Was eating, drinking, and marrying the sin that brought judgment in Noah's day?
No. Eating, drinking, and marrying are not inherently sinful; the text presents them as legitimate human activities. The judgment came because people were so consumed with mundane, materialistic pursuits that they remained unaware until the flood finally took them away.
Les explains that Jesus, speaking in Matthew 24:37-39, compares the days of Noah to the coming of the Son of Man. He notes people were eating, drinking, marrying, and giving in marriage. Les asks if there is anything wrong with that and answers no—daily food and drink, weddings, and restarting families are not wrong. That wasn't the problem. It does not show these as the cause of God's wrath. Instead, they were so occupied with human, mundane events until the day Noah entered the ark. Verse 39 says they knew not until the flood came and took them all away. Les adds that Luke 21 even mentions they builded. The issue was their materialistic preoccupation, not the activities themselves.
For as in the days that were before the flood they were eating and drinking, marrying and giving in marriage, until the day that Noe entered into the ark,
More Questions
What was actually wrong with the people in the days of Noah?
The real problem in Noah's day was that the people were so occupied with human, mundane events that they kept right on doing them until the very day Noah entered the ark.