"Do not place your hand with an evildoer, etc.": If one said to him: "That man owes me two hundred dinars, and I have one witness. Come and join him, and you will get one hundred, and I, one hundred" — of this it is written "Do not place your hand, etc."
Do not place your hand with an evildoer, etc
Mekhilta Tractate Kaspa 2:14