Be Honest With All People [3:75] Some followers of the scripture can be trusted with a whole lot, and they will give it back to you. Others among them cannot be trusted with a single dinar; they will not repay you unless you keep after them. That is because they say, "We do not have to be honest when dealing with the gentiles!"* Thus, they attribute lies to GOD, knowingly. 

You Shall Not Bear False Witness [4:135] O you who believe, you shall be absolutely equitable, and observe GOD, when you serve as witnesses, even against yourselves, or your parents, or your relatives. Whether the accused is rich or poor, GOD takes care of both. Therefore, do not be biased by your personal wishes. If you deviate or disregard (this commandment), then GOD is fully Cognizant of everything you do.