# No man puts a piece of new cloth on an old garment

"No one sews a piece of new cloth on an old garment" or "People do not sew a piece of new cloth as a patch old clothing"

# the patch will tear away from the garment

If someone were to wash the garment, the patch of new cloth would shrink, but the old garment would not shrink. This would tear the patch off the garment and leave a bigger hole.