Malbim: After the first two, you will encounter people of a higher caste, who engage in Avodas Hashem.

Rashi citing Targum Yonasan: The plain of Tavor.

Malbim: They correspond to three types of Ovdei Hashem. Refer to 10:3:5:1, 10:3:6:1, 10:3:7:1.

Radak: It is Luz, which Yakov called Beis Kel. There was the Mizbe'ach that Yakov built. When Bamos were permitted, they offered on it. The place was Kadosh, and Yisraelim came to pray there in Yakov's merit. He said about this "Yihyeh Beis Elokim" (Bereishis 28:22). It was a place of prophecy - "v'Zeh Sha'ar ha'Shamayim" (18:17), i.e. the gate from when one can know what they decree, from Shamayim, about the lower beings. Hoshe'a (12:5) said "Beis Kel Yimtza'enu v'Sham Yedaber Imanu." Yonasan translated here "Olim El Elokim [Beis Kel]" as 'they ascend to serve in front of Hashem, to Beis Kel.'

Bi'ur ha'Gra (Yehoshua 16:2): Yakov called three places Beis Kel - (a) What was Luz, he called Beis Kel; (b) He built a Mizbe'ach, and called the place Kel Beis Kel; (c) After Hashem blessed him, he called the place Elokim Beis Kel (Bereishis 28:19, 35:7,15).

Malbim: He serves Hashem to be pleasing to Him, without any other intent. He offers the three parts of his Neshamah to Hashem.

Malbim: He serves Hashem for his own benefit, to receive his needs. He serves Hashem, and also himself. He offers the three parts of his Neshamah to Hashem for food.

Malbim: He serves Hashem for wealth, excesses and indulgences.