What does Judges 1:13 mean?

Caleb has issued an opportunity. He will give his daughter Achsah in marriage to whomever succeeds in attacking and conquering the Canaanite city of Kiriath-sepher, also known as Debir. The city is apparently part of Caleb's inheritance in the Promised Land. This section (Judges 1:12–15) repeats the information from Joshua 15:15–19.

A man named Othniel succeeds in capturing the city. We're told that Othniel is the son of Caleb's younger brother, meaning that Caleb is Othniel's uncle and Achsah is his cousin. Marriage among family members in this way was not unusual during this era—or most eras in history.

Caleb's absolute commitment to the Lord and boldness on Yahweh's behalf is remarkable. It's even more noteworthy because Caleb was likely a proselyte, meaning he converted to Judaism. Caleb is introduced in Joshua as the son of Jephunneh the Kenizzite (Joshua 14:6). Kenaz was an Edomite, a descendant of Jacob's brother Esau. That means that these bold, committed, faithful Israelites—Caleb, his daughter, and his new son-in-law—were all three converts to faith in Yahweh.