"Not every one that says to me, "Lord! Lord!" shall enter the kingdom of heaven. Only those that do the will of my Father, who is in heaven. Who is my mother? Who are my brothers?" And he pointed towards his disciples, and said, "They are my mother, and my brothers. Because whoever does the will of my Father is my brother, and sister, and mother."
Clearly, Jesus has put a lot of weight on "doing the will of my father." But what is that will? There are two possibilities. First, is the obvious. God spent a lot of time - about 5000 years trying to teach man what his will was and trying to get him to do it. And it was met with a failure rate of.., oh... about 100%. Given that, how likely is it that Jesus came to us to do nothing more than reiterate, all over again, the same policy that had failed repeatedly, over 5,000 years, and in every single one of millions upon millions of attempts?
What does that mean if you are one of those who believe that Jesus came to "be an example" to us? If you believe that, then you are trusting in yourself - your ability to do what you see Jesus do. Men have spent the past five thousand years proving that they cannot obey the law, so Jesus came to be an example of living the perfect life for what? To rub our noses in it? A sort of "nyah, nyah, look what I can do that you can't...?"
Or is it something else? Some other reason that He came?
Sure, in some things, it's clear that He intends us to follow his example. But in what? He says that to enter the Kingdom of Heaven, we must do the will of His Father... And yet the law itself testifies against us that we cannot.
So what does it mean, then, to do the will of my Father? It's pretty obvious that Jesus' command to "do the will of my father" is not simply yet another siren song from yet another prophet. So what is the will of his Father in heaven if not that they obey the commandments and lead perfectly righteous lives?
As luck would have it, Jesus Himself addressed this very question. "And here is the will of my father: that you believe in him whom he has sent."
In the Bible, the word we have translated as "believe" means far more than just intellectual assent that we typically think of when we say "I believe..." The word means to believe something to be true; but to believe it to the point of putting confidence in it, and trusting it.
The beginning is to "believe in him whom he [God] has sent." But what, we might ask, does that mean? Believe what?
Simply read the New Testament, beginning with the Gospels (Matthew, Mark, Luke and John) and believe what is written there about Jesus Christ, and believe what he has said.
That's all. That really is all. Out of that will come flowing all the other works of God that he desires of you. They will flow as naturally as water from a river, out of the grateful heart that finally sees what wonderous works have been done for them.