To borrow(front, cuff) something to give back later or turn into money to pay back.
Receiving credit off the strength of who you are.
The ‘arm’ symbolizes strength of who you are that gives you the capability to get something with no money down because of the strength of your character and nobility; being trustworthy.
‘Can I get the next one on the arm?’
‘I’m strapped for cash, can I get this one on the arm and pay you back Friday?’
‘Papi let me get it on the arm cuz I told him I didn’t have enough to go check him’
This is a phrase coined by C Haddon Chambers and it can be taken to mean either :-
1. The broad far-reaching power or influence of coincidence;
or
2. Things just happen;
Note: See also Shit Happens
Why is it that everything Malcolm does turns to rat shit?
That's because it's Malcolm, not even the long arm of coincidence.