The essence of temptation is the invitation to live independently of God.
—Neil Anderson
If temptation is an invitation, then one might think of sin as the acceptance of that invitation. This realization helps bring sharply into focus the fact that sinful living does not consist primarily of "performing wrong acts" but living with the wrong goal, or better, the wrong master.
This is not to say that sinful actions are not sinful; many (if not all) such actions are sinful not so much because of the act itself but because of the attitude underlying it: selfishness. To love someone as Jesus commanded is to seek that person's best interest regardless of consequence. Proper motivation for such love and service is understanding God's love and provision in Christ for me.
When I accepted Jesus Christ as my savior and confessed Jesus as Lord of my life, I died to my old master (sin) and became alive to my new master (righteousness.) I died to my old master (self) and I live for my new master (Christ.) This foundational truth permeates scripture, but I especially like 2 Corinthians 5:15 which says
...He died for all, that they who live should no longer live for themselves, but for Him who died and rose again on their behalf.
Looking back on my Christian life so far, I find that there were sinful acts that I used to but no longer engage in; however, they did not cease because of my efforts but because of God's efforts--Christ's life in me, teaching me, growing me, giving me proper focus. I am now able to
not sin in those ways because I learned from God in Christ that he is trustworthy in those areas and I do trust him. In areas of my life where I have yet to learn to trust God, I still experience failure by living selfishly--or to put it bluntly, I still sin.
I find then, especially since
all of my sins were dealt with at the cross, that to cease from sin is the wrong goal for me, indeed for any Christian. Whenever I have expended effort toward that end, I end up focussed on and mired in the sin. The right goal is to know God better and better; he reveals himself through his word, and as he enlightens me and I see that he is trustworthy in that area of my life too (whatever it is,) I live depending on him, and the behavior takes care of itself.
The key lies in knowing the truth and being set free by it. When a temptation whispers in my ear, I play it against the truth and believe and act on the truth.
Sin is still sin, and God's grace is not license to do anything one wants. With freedom comes responsibility. But being free means that I no longer have to worry about my worthiness (Christ is my worthiness.) I can joyfully focus on my relationship with God and the people he has placed in my life.