The most common and most likely answer to this crossword clue is the 4 plus 2 plus 3 letter word LAND OF NOD
I've seen this crossword clue in Financial Times
L
A
N
D
O
F
N
O
D
Buddy explains!
The straight part
We know that "Sleep/biblical place" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sleep/biblical place = land of nod.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.