Augustine of Hippo
Catena Aurea · Matthäusevangelium 5
Think not that I am come to destroy the Law, or the Prophets: I am not come to destroy, but to fulfil. For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled. Whosoever therefore shall break one of these least commandments, and shall teach men so, he shall be called the least in the kingdom of heaven: but whosoever shall do and teach them, the same shall be called great in the kingdom of heaven.
(ubi sup.) Otherwise; he who breaks the least of these commandments, that is, of Moses’ Law, and teaches men so, shall be called the least; but he who shall do (these least), and so teach, shall not indeed be esteemed great, yet not so little as he who breaks them. That he should be great, he ought to do and to teach the things which Christ now teaches.