What is a Christian
What is the proper definition of a Christian?
Matthew 22 is what first came to my mind when I saw your question:
Jesus declared, “‘Love the Lord your God with all your heart and with all your soul and with all your mind. This is the first and greatest commandment.’
And the second is like it: ‘Love your neighbor as yourself.’ All the Law and the Prophets hang on these two commandments.”‘
I believe a person who is following these commandments is a Christian.
What do you think Jesus meant in this verse?
Luke 22:32 But I have prayed for thee, that thy faith fail not: and when thou art converted, strengthen thy brethren.
Couldn't put it better. If we love the Lord with all our heart, mind and being we will be concentrated on Christ and his cause not on ourselves.
I believe what Jesus meant was that Simon Peter would turn back to the Lord with a renewed mind. My understanding is that the apostles received the Holy Spirit after the resurrection of Jesus Christ when they were gathered together and Jesus went in their midst.
Before Jesus went to the cross they still walked in their flesh although they sincerely loved the Lord.
I could be wrong but this is my evaluation.