דברי הימים א, פרק ב׳, פסוק י״ט

Following the death of his wife Azubah, Caleb marries another woman named Ephrath [מלבי״ם, ביאור שטיינזלץ]. The need for this marriage arose because, up until this stage in his life, Caleb only had a daughter and grandchildren through her, but no sons of his own [מלבי״ם].

Although few details are explicitly provided about Ephrath, rabbinic tradition identifies her as Miriam, the sister of Moses [ביאור שטיינזלץ]. From this union, she gives birth to a son named Hur. This is the same Hur who appears prominently in the Torah, closely accompanying Moses leading up to the events at Mount Sinai. Moses granted Hur great authority and trusted him completely. This close relationship and profound level of trust become entirely clear given their family connection, as Hur was actually Moses's nephew, the son of his sister [ביאור שטיינזלץ].