No one puts a patch of new cloth on an old garment, because it will tear away completely from the garment, and a worse tear will result.
Here Jesus explains in a figurative way the relationship between the new and the old orders. The new patch, which has not yet shrunk, if placed on an old garment, will dare to tear the old, bringing an even larger tear—that is, making the problem worse. This example is used to help people understand that the new teachings Jesus brought cannot be disorderly mixed into the old system. It is, in itself, a new way that must be practiced in a new manner, without confusion. On the other hand, it is important to understand that Jesus’ teaching does not erase the old, but raises the spiritual principles hidden beneath them to an even higher level.