Having the power of vocation to take article by order to The Bar (7,3,5)

'having the power of vocation' is the definition.
I don't know anything about this answer so I cannot judge whether this works.

'take article by order to the bar' is the wordplay.
I cannot quite see how this works, but
'take' could be 'callin' (calling in is a kind of taking) and 'callin' is located in the answer.
'article' could be 'the' (the 'definite article' part of speech) and 'the' is found within the answer.
'order' could be 'o' (abbreviation e.g. in British honours OM, OBE etc.) and 'o' is found in the answer.
This explanation may well be incorrect...

'to' acts as a link.

Can you help me to learn more?