People find it difficult because they think that “sainthood” or “sinnerhood” is based on your actions. 

The people in the “sinner” camp think they are sinners because of their actions. Therefore, when they hear people from the “saints” camp, calling themselves righteous, they think it’s arrogant because from an ‘action standpoint’ there isn’t anyone that has lived a life free of sin (which I absolutely agree with, that’s 1 John 1:8). So from their standpoint, it would be arrogant to call ourselves “righteous” when our actions aren’t consistent with that. 

“For as by one man’s disobedience many were made sinners, so also by one Man’s obedience many will be made righteous.” - Romans 5:19

The distinction is here. The people in the “saint” camp are professing righteousness not based on their actions. They proclaiming “sainthood” based on becoming righteousness through Christ (2 Cor 5:21) as shown in the verse above. It isn’t an assessment based on our actions, we are just agreeing with what is said about us in scripture.

It is absolute humility to say about yourself what God has said about you. Why? Because you didn’t do it to you. We weren’t made righteous because of righteous acts, neither are you made a sinner because you sin (Romans 5:19). You are a sinner because you were born in it. You are a saint because you were re-born in it (hence, born again). 

Even if being a sinner was based on your actions, God still wouldn’t call you a sinner because doesn’t even remember your sin (Heb 8:12, 10:17). Like.. does. not. remember. No recollection. Like.. as if it never happened. So even from God’s standpoint, you’re righteous. 

We don’t try to ‘argue’ for the sake of arguing theology. We preach this stuff because understanding this is what gets you free from habitual sin. 

Sinners sin. It’s their nature to. So if you believe yourself to “be a sinner”, you will reproduce exactly that. Sinners can only, at best, act righteous. They do not have freedom to behave other than what their nature dictates. So essentially, that’s what most church folks live in. “Sinners” who struggle to live righteous. 

Because they don’t know that they’ve been given a new nature to be righteous, thinking themselves to still be sinners, they struggle and struggle never breaking free. Why? Sinners will always be slaves to sin. 

But the moment they realize (renew their mind) the fact they have been crucified with Christ (Gal 2:20), that their past lusts and desires are dead (Gal 5:24), and as a result, they are no longer slaves to sin (Romans 6:6-7,11) but slaves of righteousness (Rom 6:18)… then they will walk in that freedom. 

Saints live righteous. It’s their nature to be righteous. That is what they naturally do. At worst, they will act like sinners. They have been freed from their past nature, so they have liberty to live righteously (Gal 5:13). They are free from sin. 

This is the point of telling people about their new nature, “things I write to you, so that you may not sin” - 1 John 2:1

Does that help?

In terms of confidence, I think Steve Thompson did a good job elaborating on that:

http://www.youtube.com/watch?v=gadcfayuS50