Should I do business with non-Christians?
Certainly none of us can go through a day without interacting with non-Christians.
However, when we have decisions to make about contractual work or other types of business where our quality of life will be affected, we will be better off entering into relationships with people and companies with good reputations and high integrity.
Let God guide you. In everything we do in life, if we will simply seek Him for direction and allow Him to unfold His plan for us, we can be happily surprised when we see the outcome.