False Disciples
Jesus had many disciples, people who followed him for many reasons. But, at one point, they could not accept what Jesus was saying. They stopped following Jesus and left. They thought they believed and they looked like they believed, but Jesus said they were not believers. They were false disciples. We too might go to church, generally agree with the teachings in the church, live a pretty moral life, and sometimes pray, but when it comes down to it, we may not have come to terms with the truth of who Jesus is and the truth of the gospel of the cross.
There are many kinds of false followers. Some people follow the crowd and never seriously think about what they believe, and when faced with difficulties, they leave. Some people follow Jesus for the things He can do for them, and when that does not work out, they leave. Some people follow Him to appease their guilt, but when the load is too much, they leave. Some people follow Him because they like being right, but have not submitted themselves to Jesus.
The essence of true discipleship is twofold: (1) coming to grips with the true identity of Jesus and surrendering everything to Him and learning to live for His glory; (2) coming to grips with the power that comes from eating the flesh and drinking the blood of Jesus, which means the power of the cross.