Midrash su Geremia 31:26

Our Rabbis taught: "Who is [to be considered] a common man? He who does not read the Sh'm'a, (Hear O Israel, etc.), both morning and evening," so says R. Eliezer. R. Joshua says: "He who does not put on Tephilin (phylacteries)." Ben Azai says: "He who does not wear Tzitzis (fringes)." R. Nathan says: "He who has children and does not bring them up in the study of the Torah." Achcirim says: "Even if one has studied the Bible and the Mishnah, but has failed to be in attendance upon scholars (as a disciple), he also is considered an Am. Ha'aretz. And one who only read the Bible but not the Mishnah is called a Bur; concerning one who did not even read the Bible the passage says (Jer. 31, 26) When I will sow the house, etc."