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.
All Commentaries on Matthew 5:19 Go To Matthew 5
Theophylact of Ochrid
AD 1107
The "least commandments" are those which He Himself is about to give, not those of the law of Moses. He calls them "least" out of humility, to instruct you, O reader, to have moderate thoughts of yourself as you give your teachings. He who "shall be called least in the kingdom of heaven" means he who will be last in the resurrection and who will be cast into gehenna. For such a one shall not enter the kingdom of heaven, far from it! By "kingdom" understand the resurrection.
First Christ says, "whosoever shall do," and then, "and shall teach"; for how can I guide another along a road that I have not myself travelled? By the same token, if I practice the commandments, but do not teach them, my reward is not so great. There can even be condemnation, if I do not teach because of spite or sloth.