Maybe the clearest explanation of teaching by example can be found in the book of Hebrews: "Remember your leaders, those who spoke the word of God. Consider the outcome of their way of life, and imitate their faith" (Heb. 13:7). The author of Hebrews actually called us to consider - literally, "to examine carefully" - the outcome of a teacher's lifestyle. We can get so caught up in examining a person's doctrinal positions that we overlook his or her pattern of life. But this is essential because Hebrews calls us to imitate the faith of these people. If you are going to make disciples, you need to be putting your faith into practice so that the people around you can imitate your faith.
I have always said I would not be a "do as I say not as I do" parent. I haven't found this to be a terribly difficult task up to this point, primarily because the things I have asked of my younger children have been very basic and foundational Christian priciples that even non-Christian parents teach and keep to. However, this has become a more challenging task as I try to lead my children closer to adulthood and the activities that accompany that role - driving in particular. I do not want my children driving the way I do. It's just that simple. I don't want them to talk on the phone, mess with the radio or even drive without both hands on the wheel, at 10 and 2. I don't think I am a bad driver, I just have developed some habits that are not consistent with the defensive-driver techniques I want my kids to develop. I have made an honest effort to change, but it is really hard. These are habits years in the making and it will take me a little bit of time to break them. My kids know I am working on this and we talk all the time in the car about safe driving (and they are quick to point out when I deviate from said practices). I am hoping that my efforts towards driving redemption have an impact of them, as they see me at least trying to be consistent with my teaching. I am definitely not there yet, but I am trying to work out this area of practical faith and discipleship in my life. I am sure as my children continue to grow they will expose other areas of my life that are not always in line with what I teach and I hope they will in love challenge me to walk in a way that would encourage them to imitate me. I want to live of "pattern of life" that makes both me and my kids pleasing to God.