Or HaChaim on Numbers 24:21/אור החיים על במדבר כ״ד:כ״א

1 וירא את הקיני, "He saw the Kenite, etc." This is a reference to Yitro. In order to understand Bileam we must first refer to Baba Batra 15 where we are told that the איתן of whom Bileam speaks here is Abraham. Abraham was the first proselyte; all subsequent proselytes are not only known as his spiritual descendants but are even named after him. According to Shemot Rabbah 27,6 Yitro converted to Judaism. This is why Bileam said of Yitro (Keyni) "your dwelling is with Abraham (Eytan)." He meant that Yitro's future would be parallel to that of Abraham's future. ושים בסלע קנך, "and although you have set your nest in a rock," Bileam reminds the Kenite that he has another point in his favour, namely that Yitro gave his "nest" i.e. his daughter Tzipporah to Moses as a wife. Bileam compared Moses to a rock because he was strong in Torah knowledge and had the authority of a king at the same time. Moreover, the word סלע does occur as hyperbole for Torah according to Tikkuney Ha-Zohar 21.