Children, let no one deceive you. The person who acts in righteousness is righteous, just as he is righteous. Whoever sins belongs to the Devil, because the Devil has sinned from the beginning. Indeed, the Son of God was revealed to destroy the works of the Devil. No one who is begotten by God commits sin, because God's seed remains in him; he cannot sin because he is begotten by God. In this way, the children of God and the children of the Devil are made plain; no one who fails to act in righteousness belongs to God, nor anyone who does not love his brother.
How are we sinful, fallen creatures to live up to this standard? Called to sinlessness, called to righteousness. The surrounding verses make this no easier to bear.
So, knowing that I will at some point fall into sin, I still have to act. I still have to live in righteousness in THIS moment.
Not for fear, but for love. Choose the loving thing now, this time, breath by breath.