MAT 5:19

19 Therefore, whoever annuls one of the least of these mitzvot [(divine commandments given by ]Hashem[to Moshe Rabbenu)] and so teaches Bnei Adam, shall be called katon [(least)] in the Malchut HaShomayim; but whoever practices and teaches them, this one will be called gadol [(great)] in the Malchut HaShomayim.