What does it mean to be perfect? Therefore you shall be perfect, just as your Father in heaven is perfect. (Matthew 5:48 NKJV)


So, God expects us to be perfect. What is meant by "perfect"? How can any human be without error, this side of heaven?
This question might be more suitable for Hermeneutics. But, at the same time it has some important theological value.

There is a wiki page for this verse alone.

I am not expert in hermeneutics but I believe that this verse is equivalent to this verse.


  1 Peter 1:16 (NIV) for it is written: “Be holy, because I am holy.”


One of the most important mission of Jesus while He was on earth was to make us realize that we cannot meet the standard of God in our pursuit of holiness and perfection. Jesus pointed out that violating even one law means to violate the whole commandments. Even the sinful things we contemplate in our hearts without actually doing it is equivalent to committing it in real. 

Jesus wanted to make us understand that we cannot meet the standard of God and that we need Jesus himself to set things right by pouring out His blood as a perpetual sacrifice to God. We do not need to achieve perfection but we need forgiveness. 

Therefore, we need Jesus Christ in order to be counted as perfect in the eyes of God.


  Hebrews 5:8-9 (NIV) Son though he was, he learned obedience from what
  he suffered and, once made perfect, he became the source of eternal
  salvation for all who obey him
  
  Hebrews 10:10  (NIV) And by that will, we
  have been made holy through the sacrifice of the body of Jesus Christ
  once for all.