Jesus taught that we are to be Perfect:
Be ye therefore perfect, even as your Father which is in heaven is perfect.
Matthew 5:48
Jesus would never have told us to do something that we were incapable of doing. Peter says the same thing:
Because it is written, Be ye holy; for I am holy.
1 Peter 1:16
So how can we do this? Through Faith. Believe in Jesus, be baptized, receive The Holy Spirit, and then we are to walk with God in Faith daily, being slowly transformed. God will give us a new heart to keep His commandments:
I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service.
Romans 12:1,2
And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God.
I will sprinkle clean water on you, and you will be clean. I will cleanse you from all your filthiness, and from all your idols.
Ezekiel 36:25-27
I will also give you a new heart, and I will put a new spirit within you. I will take away the stony heart out of your flesh, and I will give you a heart of flesh.
I will put my Spirit within you, and cause you to walk in my statutes. You will keep my ordinances and do them.
And ye shall know the truth, and the truth shall make you free.
John 8:32
Free from what? Sin!