Of course we have sinned! But the point of salvation is to become free of it and stop, otherwise you are downgrading the entire suffering of Jesus!
But how many times does sin even come close to something like that?
For instance not stopping to help some one along the road while driving to Church, and getting your hands dirty, just one example but there are thousands of them.
Most of what Jesus was calling sin had to do with helping others, or not helping them, that is really what it is all about, do unto others as you would have them do unto you.
Unbelief is the only unforgivable sin because if some one don,t believe, who is going to forgive them.
The rest of it is just between you and Jesus, the thief on the cross for instance was forgiven just like that, he did not have a chance to sin any more, but what if he had?
1Jo 2:1
My little children, these things write I unto you, that ye sin not. And if any man sin, we have an advocate with the Father, Jesus Christ the righteous:
Peter denied Jesus three times, even though he knew who Jesus was but as far as we know Peter was saved any way, and became a pillar of God ( in Pauls words ).
Jesus drink wine with the sinners but if some one in the church today was accused of that it would be reason for excommunication.
So different people has a different idea of what sin is, we know that adultery is sin but many Christians write down their own ideas of sin and in order to try to make it Biblical they will do a lot of half scriptures which is a lie if it is done intentionally.
12
For now we see through a glass, darkly; but then face to face: now I know in part; but then shall I know even as also I am known.
13
And now abideth faith, hope, charity, these three; but the greatest of these is charity.