In summary, Morris said three things about the paw. First, he got the paw from an old holy man, a fakir, in India. Therefore, the paw is imbued with magic and power. In particular, this paw has the ability to give three wishes to three separate people who ask for it. Two people, including himself, tried it, and it worked.
Second, the wishes that the paw grants will bring harm. This is why he tells Mr. White to be careful of what he wishes. Also at one point, he throws the paw into the fire to destroy it.
Finally, he says that the old fakir put a curse on the paw to show that people should not tamper with fate. If they do tamper with fate, disastrous results would follow.
Here is a quote that summarizes these points:
‘An old fakir put a spell on it. He was a very holy man and he wanted to show that fate ruled people’s lives, and that to interfere with fate only caused deep sadness. He put a spell on it so that three separate men could each have three wishes from it.’