This seems to have been an important teaching to Matthew. Luke records a portion of this section in his gospel, but no other gospel contains the parallel teaching to this that is found in Matthew 25. While Jesus died for all, not everyone will accept what Jesus offers. Even more difficult is the fact that not everyone who claims to follow Jesus is really following Jesus. This was not just a philosophical exercise for Bonhoeffer. The German Lutheran church was being coopted to become a promoter of Hitler’s policies.
“Enter by the narrow gate. For the gate is wide and the way is easy that leads to destruction, and those who enter by it are many. For the gate is narrow and the way is hard that leads to life, and those who find it are few. “Beware of false prophets, who come to you in sheep’s clothing but inwardly are ravenous wolves. You will recognize them by their fruits. Are grapes gathered from thornbushes, or figs from thistles? So, every healthy tree bears good fruit, but the diseased tree bears bad fruit. A healthy tree cannot bear bad fruit, nor can a diseased tree bear good fruit. Every tree that does not bear good fruit is cut down and thrown into the fire. Thus you will recognize them by their fruits. “Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but the one who does the will of my Father who is in heaven. On that day many will say to me, ‘Lord, Lord, did we not prophesy in your name, and cast out demons in your name, and do many mighty works in your name?’ And then will I declare to them, ‘I never knew you; depart from me, you workers of lawlessness.’ (Matthew 7:13-23 ESV)
One of the primary reasons that Bonhoeffer wrote The Cost of Discipleship was the practical impact of what he labeled cheap grace. Belief in the phrase, by grace alone through faith alone, was not producing disciples who were actively and visibly following Jesus. He was also aware that reacting with a religious system of works would not correct this situation. While the conflict may not be as visible as it was in Nazi Germany, we still struggle with this issue today.
This is overly simplistic, but I hope it helps. It seems to me that Jesus cares about action. Jesus said many things and His words are important. However, what really makes the difference for us is what He did. It is easy to say Lord, Lord while not surrendering my will in the least. To be a part of the kingdom I must be doing the will of the King. The will of the King is not complicated. I am to love the King and all His subjects, whether they acknowledge Him as King or not.
“What do you think? A man had two sons. And he went to the first and said, ‘Son, go and work in the vineyard today.’ And he answered, ‘I will not,’ but afterward he changed his mind and went. And he went to the other son and said the same. And he answered, ‘I go, sir,’ but did not go. Which of the two did the will of his father?” They said, “The first.” Jesus said to them, “Truly, I say to you, the tax collectors and the prostitutes go into the kingdom of God before you. (Matthew 21:28-31 ESV)
Jesus also cares about relationship. We talk much about having a personal relationship with Jesus. It is a good thing for us to know Jesus. It is essential that Jesus know us. For Jesus to know us we must be connected to Him. For most of the people I know this connection exists, but it’s like we are connected by a very large rubber band. Sometimes the connection is close, but much of the time we’re moving in the same general direction while the rubber band is getting stretched to its limit. For those who are married this should be easy to understand. My wife and I have been married over 40 years. We know each other and we still struggle to move together. Often, I’m surprised. I think she’s going to do one thing and she does another. The more common situation is that I don’t want to go where she is going. Isn’t that how it is with Jesus for us? Sometimes He surprises us, but often we simply don’t want to go where He is going.
It isn’t complicated to walk the narrow road or go through the narrow gate. Just get connected to Jesus and follow Him. It is only hard if I think I have a better idea and am determined to go my own way.