Small Errors, Big Misses
The Rule of Subtension and the Call to Return to Rest
When I was trained in artillery, I learned something called the rule of sub-tension. It’s a simple mathematical truth that carries a profound spiritual lesson. The rule states:
1 mil = 1 meter at 1000 metres.
A “mil” is a unit of angle—so tiny it’s only 1/6400th of a circle. To put it in perspective, 1 mil equals just 0.056 of a degree. If you tried to notice it with your eye, you’d hardly see it at all. It looks like nothing. But here’s the catch: over distance, that “nothing” multiplies.
So, when an artillery gun or mortar fires, at target 1000 metres away, a 1 mil error means that round lands 1 metre off target. At 2000 metres, that same 1 mil grows into 2 metres. At 5000 metres, it’s a 5 metre miss. And that’s just one mil. If you are off by 10 mils—just over half a degree—you’ll miss your target by a full 50 metres at 5000 metres. What looked small at the gun line becomes massive downrange.
That’s the spiritual truth. - Small Deviations Matter
Think of Solomon. He began with wisdom, favor, and God’s presence. But over time, small compromises—alliances, idols, unchecked desires—turned his heart. What began as a subtle drift led him far from the place of rest and obedience.
I think the biggest error impacting Christians is what Joseph Prince describes as right believing. What you believe about God can significantly impact your life and either lead you to or keep you from REST.
If you believe God is angry with you, disappointed in you, or holding your past against you, it may feel like “just a small thing.” But over time, that wrong believing pulls you further from His love and rest. You’ll live in fear instead of faith, you’ll be striving and serving till you drop instead of resting and likely live in a constant state guilt instead of grace.
Realignment is Essential
Paul writes in Romans 12:2, “Be transformed by the renewing of your mind.” Renewing isn’t a one-off task; it’s regular realignment with God’s Word. And sometimes, if not most, it takes action on our behalf.
One day I made a radical choice: to realign my life with what God’s Word says about me. Instead of focusing on my failures, I chose to look at what Jesus has already accomplished for me and what the Father declares He desires for me in Scripture. That decision changed everything. I resolved that when I sinned, I wouldn’t run away from God in shame like Adam and Eve did in the garden—I would run straight to Him. My natural instinct was to hide, but I made a conscious choice to go to Him immediately, trusting that His grace was greater than my mistakes. I made this choice because I was going through habitual sin and was sick of trying to make up for the sin I was willingly choosing to do. I decided to sit at His feet and trust His grace.
The Prodigal Son - Proof of God’s Grace and Love
Read the story of the prodigal son (Luke 15:11-32). It’s often used as a great picture of salvation, showing Our Heavenly Fathers reaction to someone being born again and that a great illustration to use, because it’s true. But take a closer look. The prodigal son, was his son. He was already part of the family when he took off to live life his way and deny his father. But look at what the father did. He waited every day for that boy to return. And when he did, he didn’t berate him or flog him, didn’t lecture him or ignore him…he rejoiced and threw him a party. Thats the exact picture of how God sees you, even at you’re worst and even when you’ve gone off the rails. He is standing there; arms open waiting to receive you back with great joy.
The Call to Return to Rest
Sadly, for many of us, a combination of daily life, poor teaching, personal disappointment, spiritual fatigue, or any number of other reasons has caused us to slowly drift from the truth of rest. Without even realizing it, we’ve substituted striving for surrender and performance for presence. That’s why we must return—not by trying harder, but by learning to rest through deeper trust. The longer we walk in untruth, the further we drift from God’s intended path.
That’s why the Bible calls us to meditate on the Word day and night, rightly divide the Word of truth, and guard our doctrine closely. Because truth makes us free by keeping us aligned.
And when we realign with the truth—when we reposition ourselves back to what God has said—we find ourselves returning to the only place our soul was ever meant to rest: in Him
