This verse, 1 Chronicles 12:16, is part of a larger section (1 Chronicles 12:1-40) that describes the various men who came to support David as he was consolidating his power and preparing to become king over all of Israel.

Here's a breakdown of the meaning:

"Some of the children of Benjamin and Judah": This indicates that people from the tribes of Benjamin and Judah, two significant tribes in Israel, were joining David's cause. Judah was David's own tribe, and Benjamin was the tribe of the previous king, Saul. Saul's lineage was still a powerful force, and getting support from Benjamin was crucial for David's legitimacy.

"Came to the stronghold": David was not yet king and was essentially operating as a leader of a band of warriors and outcasts. He was based at a "stronghold," meaning a fortified place or refuge where he could defend himself against his enemies, primarily Saul and his loyalists. Examples of these strongholds are mentioned elsewhere, such as Ziklag or Adullam.

"To David": These men recognized David as the rightful leader and came to offer him their allegiance and military support. They saw him as the future king chosen by God, despite the current political situation.

In summary, the verse signifies that David was gaining support from key tribes in Israel while he was still operating as a fugitive or leader of a rebel group. It highlights the growing recognition of David's divinely ordained role as king, even among those who might have been hesitant or loyal to the previous king.

This verse is important for understanding the following:

David's rise to power: It shows how David gradually gained legitimacy and military strength by attracting followers from different tribes.
Tribal dynamics: It reveals the shifting allegiances and political landscape of Israel during this transitional period.
Divine plan: The fact that people from Benjamin, the tribe of Saul, were joining David suggests that God was orchestrating events to establish David's kingship.