So, first of all, Christians must be like their neighbors in the food they eat and clothes they wear, their dialect, general appearance, work life, recreational and cultural activities, and civic engagement. They participate fully in life with their neighbors. Christians should also be like their neighbors with regard to excellence. That is, Christians should be very good at what others want to be good at. They should be skillful, diligent, resourceful, and disciplined.
Second, Christians must be also unlike their neighbors. In key ways, the early Christians were startlingly different from their neighbors; it should be no different for us today. Christians should be marked by integrity. Believers must be known for being scrupulously honest, transparent, and fair. Followers of Christ should also be marked by generosity. If employers, they should take less personal profit so customers and employees have more pay. As citizens, they should be philanthropic and generous with their time and with the money they donate for the needy. They should consider living below their potential lifestyle level. Believers should also be known for their hospitality, welcoming others into their homes, especially neighbors and people with needs. They should be marked by sympathy and avoid being known as self-serving or even ruthless in business or personal dealings. They should be marked by an unusual willingness to forgive and seek reconciliation, not by a vengeful or spiteful spirit.
Timothy J. Keller, Center Church: Doing Balanced, Gospel-Centered Ministry in Your City (pg. 282-283).