Indeed there are those who are last who will be first, and first who will be last. (Luke: 13:30, New International Version)

In the quoted verse, there are two relative clauses modifying "those", it sounds very strange to me.

Can anyone tell me more about the structure of the double relative cluase?

Thank you very much for your reply.
In this case, the first relative clause defines the group of people being spoken about: those who are last.
The second relative clause restricts that group even more: who will be first. Presumably then, there are also those who are last who will not be first. This structure fits most comfortably with "There is" or "There are", as seen here. Two such clauses in a row is rather unusual in general, and the idea underlying them is more often expressed in some other way.

There are ideas which are strange which are useful. (There are strange ideas which are useful. There are strange but useful ideas. Some strange ideas are useful.)

I am writing a thesis about the adjective clause including the double adjective clasue: here is the proposal
[Link deleted-- please do not post direct links to downloads-- MM]

You can have my full thesis after I finish it on May this year.

Hope you enjoy it.