Be ye therefore perfect, even as your Father which is in heaven is perfect. - Matt 5:48
God gave us a commandment to be perfect, however, what is perfection in God's eyes? Well, to approach this question let us first examine the reality of our salvation.
For by one offering he hath perfected for ever them that are sanctified. - Heb 10:14
The scripture lets us that God has perfected us? How have we been perfected? Therefore if any man be in Christ, he is a new creature... (2 COr 5:17). If you have the Holy Ghost, Christ is in you and you are in Christ - guess what Christ is a perfect Spirit. Being in Christ the perfect Spirit enables us then to live a life exactly as He would. We simply have to choose to do so.
Now back to our question. What is perfection in God's eyes? Well, it is two-fold.
1. It describes the work God has done when He sanctified us at salvation
2. It is when a son of God chooses to use his God-given ability to obey God in all things and at all time.