Jesus described His disciples as salt and light. These terms identify influence in the realm to which they are applied. Thus, Christians are to be an influence in the world.
Our influence is determined by words, attitudes, conduct / behavior, and activities.
Christians have been known to get as close to the line of worldliness as possible in order to have this influence. Many have selected close relationships with non-Christians with this in mind. Sadly, the influence is often reversed and Christians can be drawn away from their convictions.
Let us be careful how we influence others.