Genesis 46:9, "The sons of Reuben: Hanoch, Pallu, Hezron, and Carmi," is part of a list of Jacob's (also called Israel) descendants who migrated to Egypt with him. It specifically names the four sons of Reuben.

Here's what it means in context:

Genealogical Record: This verse is primarily a genealogical record. It's a way of documenting and tracing the lineage of the Israelites. It shows the direct descendants of Jacob.
Reuben's Legacy: It establishes Reuben as the progenitor of these four families or clans. His descendants will be known as the Hanochites, Palluites, Hezronites, and Carmites (although the specific names of their descendants are detailed elsewhere in the Bible).
Foundation of the Tribes: These sons represent the foundation of one of the twelve tribes of Israel – the tribe of Reuben. Their families would grow into a significant group within the Israelite nation.
Historical Significance: The inclusion of this list in Genesis emphasizes the historical and familial connection between Jacob's family and the Israelite people. It underscores the promise made to Abraham that his descendants would be numerous.
Fulfillment of God's Promise: It is a testament to the fulfillment of God's covenant with Abraham and his descendants, promising to make them a great nation.

In short, this verse is a simple statement of fact: these were Reuben's sons, and therefore the founders of the major family groups within the tribe of Reuben. It's important for understanding the tribal structure of Israel and the historical development of the nation.