“After the seven days” — What is the nature of these seven days? That the Holy One, blessed be He, watched over (mourned for) His world for seven days; and from here [we learn] the seven days of mourning.
On the daf / in context: The seven-day delay is read as a divine period of mourning for the world that was about to be destroyed. The passage is also cited as an asmakhta for the rabbinic institution of seven days of mourning.
Type of Learning
Custom (source / asmakhta for the seven days of mourning).
What Is Learned
The seven days before the Flood serve as a model (or support) for the seven days of mourning observed for the dead.