People don't like hypocrites. I don't like them either. I remember as a teen my stepfather, cigarrette clenched in his pointing fingers, emphasizing that I should not smoke. "Do as I say; not as I do!" was the message, and hypocrites are good scream that message. They tell people what to do, and then try to hide the fact that they are not living out what they are telling others to do.
Sometimes people arelabeled as being hypocritical because they are not being open about their struggle. They know how they should live. They know it is the right way to live. But they are unable to live it out themselves. They struggle with the problem. Everyone struggles to reign in their problem. The hypocrisy happens when they are not honest about their struggle. They put on their happy face, because that is often what is expected, and play the good Christian. How much better would it be if someone simply said, "I know such-and-such is the right thing to do. I am not perfect at doing it, but I believe that is the right direction to go." These people, while not trying to be hypocrites, are labeled as such because of their inability to be open with others.
Sometimes people are just downright hiding their sin. They tell people how THEY should live, but fail to apply the strict standards to themselves. Those people irritate us all, but they should not be seen as the example of everyone in the church. Just so everyone knows, those people irritate those who are actually trying to live out the principles of Jesus.
The phrase "Practice what you preach" at first seems like it is easy enough. A person is simply expected to live they way they say life should be lived. This is a well and good until you consider that those in the Christian faith are not called to practice what they preach, they are called to practice what Jesus preach, and that is even harder. If I have to live by what I preach, I am going to preach an easier way that of Jesus.
It gets even tougher when you realize that Jesus did not simply spout off a list of rules. The Pharisees were already living by an extensive set of rules called Torah. They lived by the yoke of the Rabbi under whom they served. Many of them could honestly say they were "blameless" according the Law because they obeyed every jot-and-tittle of it.
This seems like is should be good enough. It should be good enough that they obeyed every statement in the law. But Jesus said there was something they lack. They cleaned the outside of the cup, but the inside was filthy. Jesus called the Pharisees "whitewashed tombs."
Why was perfect obedience to the Law not enough? Because you can obey every single law ever written, and still not be the kind of person on the inside that is obedient. In Matthew, Jesus uses an ironically humorous story illustrate this fact. Read Matthew 5:29-30. "If your right eye causes you to sin, gouge it out and throw it away. It is better for you to lose one part of your body than for your whole body to be thrown into hell."
If simply not doing something was the point, a person could gouge out their eyes and cut off their hands. They could become a human stump, and that would keep them from doing anything wrong. But even without doing anything wrong they could still be an evil person on the inside. This is why legalism NEVER works. It either creates arrogance or it creates compliant followers who are not changed on the inside.
Jesus does not expect us to simply obey the command, He desires us to become people who obey out of who we are at the core of our being. We are not simply to obey, we are to BE obedient people. There is a very big difference.
As we immerse ourselves in the spiritual disciplines and practices we open the path for God's grace to transform the "old man," as Paul says, into someone who exhibits the fruits of the Spirit. It may seem oxymoronic to talk about grace and "doing" as though one is dependent upon the other, but in a way they are dependent upon each other. Let me illustrate: if you never show up to the gym, you are never going to get into shape.
The purpose of being a disciple of Jesus Christ is not to escape hell for heave; the purpose of being a disciple is to reclaim the life God intended us to live. That life is a life of holiness in the character of Jesus Christ. This life cannot be created on our own, it is truly a result of God's grace.
This process of developing a Christlike character will take a lifetime. There will be times of failure and falter, but there will be times, empowered by the Holy Spirit, of great advance and growth. God's grace continually draws us deeper and closer. We should never pretend that we have everything figured out, nor should we put on a face (hypocrite in NT Greek is the same word as "actor" meaning "to put on a face") that makes us look like something we are not. We must be honest with our struggles, but not wallow in defeat either.