2 John 1:8 "Watch out that you do not lose what we have worked so hard to achieve. Be diligent so that you receive your full reward."
Lose what? What work? What reward?
We have will lived for ourselves and have done our will. We had a faith that wasn't beneficial for our spirit, rather for the flesh & carnal things. However, the moment we accept Christ, we receive a "new" life and a "new" faith which is now directed to God. But it doesn't stop there, God begin to work in us and we join him in the full-time faith-work.
What God desires for us not to lose is our faith. If you think how far we have gone and how much we faced, is it truly worth it to let go of what we have received from God? We work out our faith like a muscle so that it can grow and become strong. We aim to achieve holiness. Holiness is the level where you rise closer to God. And the closer we are, the father we are from the world and all it offers.
God rewards his people when they do right. Even the grace and mercy of God is a reward. A reward is a gift, something that advances us. Doesn't the grace and mercy of God takes us forward. God gives us several rewards, but the full reward is heaven, our home. Yes, even a new home is a reward. We are to do the work of God here on earth, and we will reap the reward after this earth