This is what the Torah intends when says: vehalaktha bidrakhav "And you shall conduct yourself -in your daily life- in His paths". (Debarim 28, 9).
Think of of a person, who is considered knowledgeable in Real Estate, and he is asked by a friend or family member, to give his advice about buying certain property that just came to the market. This person, instead of telling truthfully that it is a good deal, lies saying that he is not sure about it, or that something might be wrong with that property, because he is interested in acquiring that property for himself. The same applies for example in the area of Shidukhim -dating- . If someone asks your opinion about certain girl -which you consider her to be a very
good person- but you don't give a good reference about her, because you're interested in her for yourself. These are all examples of harmful lies.
In all these cases, when a person is asked to give an opinion, and he tells the truth, despite having a conflict of interest, and he sacrifices his own benefit for the sake of the truth, this person is behaving with real yrat shamayim, fear and respect of God, and is "conducting himself through the paths of God".
Rabbi Yosef Bitton. YMJC | 130 Steamboat Rd. | Great Neck | NY | 11024