Paul writes to Timothy in 1 Timothy 4:12, "Let no one despise your youth, but be an example to the believers in word, in conduct, in love, in spirit, and in purity. Till I come, give attention to reading, to exhortation, to doctrine..."
As Christians, we are well aware of the fact that we need to be a good example to non-believers, but we don't often think about those who are already followers of Christ. In truth, we need to be just as much of a good example to them as we are to non-believers. Paul gives us a whole list of areas here in 1 Timothy where we need to make sure we're being a good example. We need to be a good example in our words, our actions, our love for one another, our spirits, and by keeping ourselves pure.