Impossible? Yes, if we rely on our own strength and resolve. The strength come from the Spirit. And the resolve comes from remembering how God has treated us: "He is kind to the unthankful and evil. Threrefore be merciful, just as your Father also is merciful".(Lluke 6: 35-36) That's a life we all long to see. Christianity is not just Christ in you, but Christ living His life through you.