Actually, if you will read the rest of Matt 5 you will find that he is talking about the laws, the social laws, pertaining to how people live together.
The full quote is
18: 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.
He then goes on to expand some of the laws for example, expanding killing to just being angry without cause.
So the section that you quote simply shows that things do change and that what is written will, and should be only a guideline.
Aslan is not a Tame Lion