This is a question that implies a destination and an accomplishment. Sure, it is not our own accomplishment, for we are saved by grace, but it is a finished act nonetheless. And it is a wrong question.
Look at what Peter says here:
By his divine power the Lord has given us everything we need for life and godliness through the knowledge of the one who called us by his own honor and glory. Through his honor and glory he has given us his precious and wonderful promises, that you may share the divine nature and escape from the world’s immorality that sinful craving produces.
How can something be completed when we are talking about the divine nature–something that is infinite? If our relationship with Christ is us “sharing the divine nature” then we are going to be ever-deepening and being transformed. Peter says as much with the next three verses:
This is why you must make every effort to add moral excellence to your faith; and to moral excellence, knowledge; and to knowledge, self-control; and to self-control, endurance; and to endurance, godliness; and to godliness, affection for others; and to affection for others, love.
If something was completed, there would be no need to add to it. But as it is, we are talking about God’s very presence in our lives transforming us into the likeness of Christ (sharing the divine nature), and there will always be room for addition and growth. This is what Methodists call pressing on towards sanctification. God continually transforms us more and more fully into his own likeness, and because he is infinite there will always be more room for growth.
It is as if we stand in a darkened room and light a candle. We can now see in the room, but not completely. There are still areas that are dark. If we have more light than the candle, if we turn on a lamp, we will see even more of the room, but still not all of it because there will be shadows in the corners. Finally, if we open the windows and let the sun shine in the room, we will be able to see all of the room. As we experience more and more of God’s grace, of the divine nature in our lives, we will have more and more sin rooted out of our being. And here is where the analogy breaks down. There will come a point when an room is entirely lit because of the sun and everything is seen. Not so with God’s grace. Because God is infinite, there will never be a time in this life when we will be completely transformed so that no further growth can take place.
There is always more to the divine nature, and there is always room to grow. In fact, if we are not growing in our likeness to Christ, if we have stagnated, if we rely on the fact that we “are saved,” then we are rejecting God’s grace and his divine nature in our lives. We, in essence, say to God, “Thank you, but I am fine now. I no longer need any more of your presence in my life.” God forbid we should ever say such a thing!
Do not rest in “Are you saved?” Grow in “I am being saved.”