Now, just one comment, speaking freely.
If one believes that a Christian can live without sin, regardless of what anyone has said, how do you define sin?
If one ever has an uncharitable thought, ever for a moment feels a desire to have something that doesn't belong to them, feels the slightest flash of irritation if someone cuts in line in front of you, fails to do every single good thing you possibly can do - one has sinned.
It is a valuable and even expected effort that we should fight against such passions, beginning with the most offensive and outward ones, and as life and grace permit, proceeding to work on even the smallest ones known only to ourselves and God ... that is the Christian struggle against the flesh.
But to claim we have achieved that level of sanctification is to deceive ourselves - in such a case we would have to be blind to our true state.
It is a battle that continues as long as we are in the flesh, or should.
But no Christian should be committing ongoing, habitual, freely chosen sin. That is the very first level we overcome, by the grace of God, as mere babes in Christ, unless we resist His grace and then we need to examine ourselves to see if we are truly in the faith at all.
God be with us all.