And he spake also a parable unto them
The Scribes and Pharisees; illustrating what he had just now said:
no man putteth a piece of a new garment upon an old;
by "a piece of a new garment" meaning the new and upstart notions and traditions of the elders, which were so in comparison of the law of Moses; and by the "old", the robe of their own righteousness, wrought out in obedience to the moral and ceremonial law: and Christ suggests, that to join these together, in order to patch up a garment of righteousness, to appear in before God, was equally as weak and ridiculous, as to put a piece of new and undressed cloth into a garment that was old, and wore threadbare.
If otherwise, then both the new, maketh the rent;
that is, much worse than it was, as it is expressed both in Matthew and Mark; the old and new cloth being unsuitable, and not of equal strength to hold together: by this Christ intimates, that the Jews, by being directed to the observance of the traditions of the elders, were drawn off from a regard to the commandments of God; so that instead of having a better righteousness, they had one much the worse, a ragged, and a rent one.
And the piece that was taken out of the new, agreeth not with the old;
and so the statutes of men, and the ordinances of God, or the traditions of the elders, and the commands of God, are no more like one another, than the piece of a new and an old garment, and as unlike is obedience to the one, and to the other;
(See Gill on Mark 2:22) where this, and the following parable, are more largely explained.