Jesus doesn’t tell us to go out there and do the best we can. He said, “Be ye therefore perfect, even as your Father which is in heaven is perfect.” (Matthew 5:48)
We naturally say, “Impossible!”
To which Jesus replies, “With men this is impossible; but with God all things are possible.” (Matthew 19:26)
See the Bigger Picture
Without Jesus we cannot save ourselves, we cannot cleanse ourselves, we 
cannot heal ourselves, we cannot changes ourselves, and we cannot be perfect, but in Christ Jesus we can do all things through Him who strengthens us. (Philippians 4:13). That of course means all things that are pleasing to Him, bless Him, and are of His good will and pleasure.
But we lament, “We will fail.”
Two things: Making a mistake does not negate perfection, nor is making a mistake failure. Failure is when we make a mistake and refuse to learn from it. Failure is when we fall down and refuse to get up. Failure is when we make one mistake and think two good deeds will balance the scales. Failure is when we reject God and try to fix it ourselves. Failure is what negates perfection.
Perfection is Already Ours
“He has clothed (us) with the garments of salvation; He has covered (us) with the robe of righteousness.” (Isaiah 61:10) In other words, we are dressed to perfection. Yes, we are works in progress. Yes, we are being changed daily. Yes, we are being sanctified. But in all these things if we err, He has us covered. No longer should a brother or sister in Christ declare, “I’m not perfect,” because in Christ Jesus we are, so we should start acting like it.
Sharing Our Perfection
Our most perfect possessions are our salvation and the ‘Good News’ of the Gospel message. I suggest this is what we share.
“Go ye therefore and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost.”
(Matthew 28:19)
He Dwells -- The B'log in My Eye 