Thou shall not bear false witness against your neighbor
This commandment has a fairly agreed-upon interpretation by Jewish and Christian scholars and theologians. This interpretation is made easier as there are other instances of commands by the Lord which instruct to be equitable to neighbors.
"Love thy neighbor as yourself." - Mark 12:31
In Jewish theology, lying is one of the things that God hates. This notion is states a bit differently in the New Testament. Jesus says that false testimony is among the things that defile a person.