That's not a real job. That's a scam.
The money inbound to your account will seem legitimate, but will later reverse "bounce". The money outbound from your account will be irrevocable.
For instance, they will transfer $12,000 in, and have you transfer $10,000 out, and you're told the $2000 is yours to keep. Later, the $12,000 will reverse, leaving your account overdrawn by $10,000. Your bank will come after you for that, and you will say "try to recover the $10,000” and they will try and be unable.
When you are unable to give them $10,000, they will start litigation against you and will also mark you in the ChexSystems blacklist. The knock-on effects of this will be a low credit score, and you will not be able to open a checking account for 7 years. This will make you among the "unbanked". If you wonder who willingly pays 7% to have their checks cashed at those pink check-cashing shops, that's who.
The money is from hacked accounts...
Many kinds of hacked accounts could be involved. That can include hacked bank accounts, or Social Security accounts - many seniors don't bother signing up for Social Security's online account, so hackers do it for them, and redirect their SS payments to somewhere else... That's where you and your account comes in. This type of fraud takes months to unravel, and so may roll for awhile. Later, when SS catches up with you, if they can't immediately claw it back, well, they have your number. and they can wait. When you retire and they're paying you your Social Security payments, they can tap it.
... Or money laundering
There's an outside possibility the money is genuine and will remain in your account. Unfortunately, the source of the money is crime, and it's likely to be tailed by Police , DEA or Secret Service. They will confiscate all of the $12,000 they can get. They might also try to prosecute you for money laundering, but you'll likely be able to get out of that.
Regardless, even if everything was legit, doing what they want you to do would be a violation of other banking laws which are designed to prevent money laundering, since you are acting as a bank.
The $10,000 has been laundered, and will go on to be used for bad things. Not least, this is how terror is financed.