Actually satan is self employed and does not work for the Lord.
I'd be interested to know who told you this?
If you want to use the bible as your means of confirmation then may I suggest the following.
Jesus was led into the wilderness by the Spirit He just received to be tempted
by Satan.
Satan sifted Peter.
Paul said, hand them over to Satan for the destruction of their flesh.
Deceiving spirit used by God in the king Ahab's downfall.
Then a spirit came forward and stood before the Lord, and said, ‘I will persuade him.’ The Lord said to him, ‘In what way?’ So he said,
‘I will go out and be a lying spirit in the mouth of all his prophets.’ And the Lord said, ‘
You shall persuade him, and also prevail. Go out and do so.’ Therefore look!
The Lord has put a lying spirit in the mouth of all these prophets of yours, and the Lord has declared disaster against you.”
God shall send them strong delusion, that they should believe a lie:
God gave mankind free will by crating us in His Own Image and when man turns away from the Lord the devil has legal right to attack them so no need to blame God for that or falsely claim the Lord hired satan and his demons to do some dirty work.
I'm not too concerned about anyone's ability and freedom to choose or not to choose.
I find comfort in knowing that the Creator of all things has freedom to choose to create whatever He wants and for whatever purpose He chooses.
I will elevate our Creator not so much His creation.