Hi Edward, I think what is in view here is the "position" and the "condition" of the believer. Every time we have doubts that the Lord is Going to toss us to the Curb, we are living and thinking in our "condition". Not in our "position" in Christ.
Peter walked on water thinking in His "position in Christ" as soon as He started thinking about his "condition" he started to sink.
The Child who is holding His fathers hand is thinking and acting in His "position". Let go of that hand and we are acting in our "condition", but if we let go of that Hand are we still a Child to that Father? Our position never changes. Once a Child of God ALWAYS a Child of God. Even an earthly father would forever save that Child who let go of His hand. How much more would our Heavenly Father do for us?
Speaking of position, I came across this today and would like to hear your take on it.
2 Peter 3:17-18
17 Therefore, dear friends, since you have been forewarned, be on your guard so that you may not be carried away by the error of the lawless and fall from your secure position. 18 But grow in the grace and knowledge of our Lord and Savior Jesus Christ. To him be glory both now and forever! Amen./ (NIV)
Steadfastness is what I believe fits the original better than "position". Peter is talking to Spiritually mature believers in these verses. They already know Pauls doctrines, which are hard to understand in the first place. So Peter is still talking about their "condition", which is a spiritually mature person who has learned to be filled with the Spirit and walk in the Christian faith.
So I think the "fall" Is ones own maturity level In Christ.(drifting away from Grace and into reversionism)