What distinguishes lawful from unlawful in marriage is the duff and the voice.
What does this hadith mean?
Marriage.
Its distinguishing feature is that it is announced.
So the Prophet ﷺ said.
The Prophet ﷺ said. "Announce this marriage."
“And beat the duff for it.”
So part of announcing it is that the duff be beaten for it.
The duff is well known.
And it is a known kind that gives off.
a sound. It is a frame on which sheep skin or the like is set.
There should be no jingles in it.
Nor should it be what is called the darbuka or anything else.
What distinguishes a lawful public marriage from a forbidden secret one...
It is beating the duff. The point is to announce it, announce it.
This does not mean that a marriage where no duff was played is unlawful. No.
Rather, what is meant is that what is required is publicity.
Duff-beating is part of the announcement.
So, suppose a man got married.
And he announced it and held a feast, but no duff was beaten at his wedding.
So the marriage is valid and permissible, and there is no problem.
Rather.
Marriage should be announced.
What is forbidden is secret marriage.
One distinction between secret and public marriage is beating the duff.
For a secret marriage is not announced.
Nor is the duff beaten for it.
A public marriage is announced and the duff is beaten for it.