Old Testament figure penning account for another (5)

I believe the answer is:

jacob

I'm a little stuck... Click here to teach me more about this clue!

'for another' is the definition.
I can't tell whether this defines the answer.

'old testament figure penning account' is the wordplay.
'old testament figure' becomes 'job' (I can't explain this - if you can you should give a lot more credence to this answer).
'penning' is an insertion indicator.
'account' becomes 'ac' (abbreviation).
'job' going around 'ac' is 'JACOB'.

Can you help me to learn more?

(Other definitions for jacob that I've seen before include "Bible character - old breed of sheep" , "Name of patriarch" , "man" , "Fellow" , "Twin of Esau" .)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.