First, to put things in perspective a bit here, **Caleb was likely a foreigner and not even an Israelite. Furthermore, Caleb is most likely not even the name of a particular person but the name of a particular tribe or clan which dwelled in the Negev**. Proof of this can be found in 1Samuel 25:3 where Nabal is identified as a Calebite. Then again later in chapter 30 David talks about the "Negev of the Calebites". All these clues suggest that the man named Caleb in the bible was a man from the Calebite clan which joined the Israelite cause to conquer of the land of Canaan. Though he clearly represented the tribe of Judah in Num. 13:6, it does not necessarily imply that he came from this tribe, but that he and his clan may have been allied with Judah, thus allowing Caleb to represent them in their expedition to Canaan. 

This answers your question; namely, why is Caleb singled out for praise when Joshua also followed the ways of God and did not protest to the conquest of Canaan. Since, as we have shown before, Caleb was a foreigner, it was unusual for him to inherit land which was promised to the Israelites exclusively (though not unheard of, see Judges 1:16 regarding the Kenites); **that is why the text repeats again and again that Caleb, since he was loyal to God and his word, will inherit Hebron and will be allotted a portion of it alongside the Israelites, although he was a foreigner.** Joshua, on the other hand, was an Israelite, so it is taken for granted that he will inherit the land and that a portion will be allotted to him. Moreover, it was expected of him to participate in the conquest of Canaan and listen to God's command to not be afraid and take it. But Caleb was a foreigner and nothing was expected of him, but as it turns out Caleb the valiant warrior performed even better than his sissy Israelite friends who were scared and terrified from the Canaanites. For this reason he was promised a nice potion of the land of Canaan, though this was unusual protocol with foreigners; and that is why he is singled out for praise and his inheritance is always mentioned alongside his name whenever he is mentioned.   

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Note that Caleb's lineage is not entirely clear as the bible *seemingly* contradicts itself a few times, sometimes identifying him as a Kenizite (Num. 32:12; Joshua 14) a tribe which are said to have dwelled in the land of Canaan (Gen. 15); and sometimes as a brother of Othniel son of Kenaz (Judges 3:9), the latter which probably refers to the tribe which has been identified as a descendant of Esau in Gen. 3:11; and then the name itself suggests that he was a Calebite. See [here][1] for more on this. It is not in my interest now to offer reconciliation of these texts, but I think, judging from the few biblical texts, we can safely assume that Caleb was not an Israelite but a foreigner.  


  [1]: https://thetorah.com/what-was-caleb-the-kenizzites-connection-to-hebron/