The Hebrew word used here was “Ereb” that literally means promiscuous
(made up of various disparate elements mixed together) mass of foreigners, strangers and wanderers – in short, “Gentiles”. Contrary to what we always knew, God saved not only the children of Israel but also those God-fearing Gentiles who believed in God and attached themselves to Israel as they were being led out of Egypt. This was a physical manifestation of spiritual truth as described by Paul in Eph 2:11-13, 19. Caleb was among these mixed multitudes of Gentiles.
The Torah (first five books of the Bible) and the Book of Joshua have many good things to say about Caleb. In Numbers 13-14, we were told that he was one of the twelve spies sent by Moses to the Promised Land. While ten of the spies were afraid of the inhabitants of the land, Caleb together with Joshua was undeterred. He tried to convince the Israelites that they could over take them, even though the enemy appeared to be more superior in stature, for God was on their side. Because the Israelites listened to the report of the majority and caved in to fear, God made them to wander in the desert for the next forty years until all the present generation of unbeliever died. Because of their faithfulness, God promised that Joshua and Caleb would enter and possess the Promised Land.
In Joshua 14-15, Caleb, now an old man, is about to take his possession. Although he was old already, he still felt as strong as he did forty-five years earlier, when he first spied out the land. Even at the age of 85, he was unafraid of the giants and high walls of Canaan. Inspired by the promise of God, he went into Hebron and took it for himself.
What is interesting about Caleb is that he was not even an Israelite, for he was the son of Jephunneh, a Kenezite (Numbers 32:12; Joshua 14:6). The Kenezites came from the descendants of Esau (Genesis 15:19; 36:11, 15, 42), and they eventually associated themselves with the tribe of Judah when they came out of Egypt (Numbers 13:6).
Why is it that the Hebrew Bible made mention of the heroic deeds of Caleb who was not even a full Israelite? For us believers, the importance of Gentiles in the Old Testament foreshadowed the time when God would later include them in His New Covenant. In the New Testament, God wants the Gentiles to become co-heir with His covenant people, without the necessity of circumcision. The Tanach (Old Testament) emphasizes God's relationship with a specific nation, the physical Israel, while the new covenant creates a new community, in which Jews and Gentiles are both part of the commonwealth as mentioned by Paul in his letter to the Ephesians.
The descendants of Caleb occupied Hebron as late as the time of king David (I Samuel 25:3; 30:14), and the biblical authors perhaps wanted to explain how they got there. Calebites had a strong connection with Israel and her God and they couldn't claim that they were full-fledged Israelites because the Calebites retained their identities as Kenezites. Therefore, they included a story about Caleb getting land in Canaan as part of the Israelite invasion to present a testimony for Israelites as co-heir of the Promised Land.
In the Bible there are passages that encourages the Gentiles to worship the God of Israel, the only one true God. It occurs throughout the books of Psalms and Isaiah. When Solomon dedicated the Temple, he said, "Likewise when a foreigner, who is not of your people Israel, comes from a distant land because of your Name--for they shall hear of your great Name, your mighty hand, and your outstretched arm--when a foreigner comes and prays toward this house, then hear
in heaven your dwelling place, and do according to all that the foreigner calls to you, so that all the peoples of the earth may know your name and fear you, as do your people Israel, and so that they may know that your name has been invoked on this house that I have built" (I Kings 8:41-43 NRSV). So the emphasis on Caleb's valour may have reminded both Israel and the Gentiles that God is faithful and He honour His promises to those who follow Him whether Jews or Gentiles but just like those who died in the desert because of unbelief, He did
not let them enter His rest whether Jews or Gentiles (Heb 4:1, 11).