Rashi cites the Sifri which interprets “your children” to be synonymous with “your students.” Indeed, students are likened to spiritual children. The Talmud Bava Basra 8b interprets the pasuk in Daniel 12:3 — sgu okugk ohcfuff ohcrv hehsmnu, “and those who teach righteousness to the multitudes [shine] like stars forever”, as a reference to Torah teachers.
Why is a mechanech, educator, compared to stars? Horav Mordechai Ilan, z.l., suggests two reasons. The rebbe must be pure, his mind and heart unspoiled. Just as the stars are distant from the earth, the rebbe’s essence is distant from “artzius,” earthliness or materialism. A rebbe is a vehicle through which Toras Hashem is imparted to Jewish children. A blemished conduit — an inappropriate teacher — should not be allowed to sully the sublime nature and inviolate character of the subject matter. A Torah teacher must always be cognizant of his awesome responsibility to transmit Torah in its quintessence.
Horav Ilan suggests another thought. One who is constantly surrounded by children, either through involvement in the actual classroom or interaction in the educational/social realm, risks becoming parochial in his dealings with people. In this pasuk the educator is encouraged to be like stars, which radiate their heavenly brilliance from a distance. This does not suggest that the rebbe ought to maintain an aloof and detached relationship with his students. On the contrary, he should be close to them to the point that the students feel an affinity with him. He simply should not permit the puerile nature of his students to influence his own personality.