William Burkitt on Matthew 5:17

Our Saviour here informs his followers, That he had no design to abrogate any part of the moral law, or to loose mankind from the least measure of their duty either towards God or man, but that he came to fulfil it:

1. By yielding a personal obedience to it.

2. By giving a fuller and stricter interpretation of it, than the Pharisess were wont to give; for they taught, that the law did only reach to the outward man, and restrain outward actions.

As if Christ had said, "Though I preach a more special doctrine than is contained even in the letter of the moral law, yet think not that I am come to destroy and dissolve the obligation of that law, for I came to fulfil the types and predictions of the prophets, and to give you the full sense and spiritual import of the moral law."