Sin is spiritual dirt we continue to cover ourselves with no matter how much we love God. We do it daily, hourly, every waking moment. Yes, there is a need for us to become pristine in order to be in communion with Him, so the answer is yes, our sins must be forgiven; we must be cleansed of all that separates us from Him. Some of that we can do ourselves, but ultimately it is God's mercy that accomplishes that.
You may have heard people of my faith say things like they want to adopt "the mind of Christ" or that we should "conform ourselves to the image of Christ"
That's part of it FK. Theosis is a way of "life in God." It is a process, a struggle in fact (Slavonic word for it is podvig), because our sin-prone nature makes it a struggle. It involves placing God first, everywhere and all the time and denying yourself. The idea is to become pure and clean so that, to paraphrase the Scripture, His light can shine through us for others to see and know Him.
It's the last part that still gets me. :) What is it that we can do ourselves, and where does the ability to do it come from? Are we born with it?
The idea [of Theosis] is to become pure and clean so that, to paraphrase the Scripture, His light can shine through us for others to see and know Him.
Sounds good to me. :)