In the mind of a first century Jew (before Jesus came along), the Pharisees were considered the most holy of all Jews. In fact, the word "Pharisee" comes from a Hebrew word that means "pure" and had the connotation of "puritan" to their ears. So then, why do we view the Pharisees as hypocrites who are the furthest from holiness? One reason alone: Jesus trashed them. He took their reputation and showed that it was all a falsehood. He exposed the depth of their depravity.
In today's gospel, Jesus tells the disciples that their righteousness needed to "exceed that of the Pharisees". For the first century Jew, Jesus' words are shocking because to their ears it sounds like "unless you are holier than the most holy you are not going to Heaven". Remember, the modern view of the Pharisees had not yet been developed so this is what they would have heard. It was only later that the Church would have heard this in a different light. After Jesus had reoriented everyone's thinking about the Pharisees, they would have heard a much deeper level of what He was saying. It would have sounded more like "if all you are doing is to follow a superficial holiness that has no real depth, then you are going to end up in the same bad place that the Pharisees are going to."
Put the two of these ideas together and you come up with our Lord saying the following: "Unless you have a diligent faith that has the highest goals and avoids that superficial practice that only looks like the highest goals, then you are just one more hypocrite." It is important for us to hear both aspects of this teaching; both what it sounded like to the first hearers, and what it sounded like years later when the gospels were first written down. They both enlighten us on what our Lord is aiming at (and help us to understand no one can sneak out of this one).
One of the things that the Catholic Church struggles with today is superficiality (people being Catholic only in name and not in actual behavior). There are many behaviors that are associated with being Catholic, but unfortunately most Catholics are not following the majority of them. It seems like today, weak faith, compromised morality and doctrinal confusion are the norm in the Church. This is the primary reason why people leave the faith: they have little to no commitment to begin with, so when there is any challenge they often quit.
If you are even moderately struggling with this, then you know it. You are aware that your faith is not devout. This does not surprise most people today. One of the biggest issues for us now is the fact that those who fall into this perilous state find many ways to justify it. "You don't need to be a supersaint to get to Heaven" (yes, I have actually heard that one); "I'm just a basic Catholic"; "the Catholic faith today is more relaxed". The list could go on and on.
So, Jesus' words in today's gospel speak to each of us. He says to our hearts: "your level of holiness needs to be more than merely the ordinary, it needs to be more than the highest". We are called to have an extra-ordinary faith. The idea that we can get by with the smallest level of effort is a lie (started by the devil, of course). So, then, when we hear this and (inevitably) react with fear ("how can I possibly accomplish this perfection?!"), that drives us to go to God for His grace to help us in this wicked world we live in.
Is your righteousness just middle-of-the-road easy believism? Is your faith "ok, but not great"? Do you think that you are doing pretty good? Wherever you may be at, your righteousness needs to exceed. It needs to be fervent, and it will only be that with the help of our Lord and His righteousness. He alone can grant us the grace to overcome and stand true in difficult times. Do not compromise by just following the easy way. Do not follow the changing streams of this world. Stand out; stand above; make it known that we stand for Christ, and Him alone.