Newton’s Third Law

See if you can finish the following phrase: “For every action, there is . . .” You’re probably hearing a distant bell ring from your physics class in middle or high school. If you’re struggling to remember the ending, it’s says, “For every action, there is an equal and opposite reaction.”

This is formally known as “Newton’s Third Law.” It derives this name from the fact that Sir Isaac Newton observed and defined this natural law in his Mathematical Principles of Natural Philosophy, over 300 years ago.

Why should you care about any of this?

Well, as it turns out, Newton’s Third Law isn’t just something to discuss in science class or tinker with in a laboratory. It’s an absolute reality that governs our earthly existence, just as gravity does. Whether we realize it or not, the fingerprints of Newton’s Third Law are on just about everything we’ll ever touch.

The evidence is all around us . . . our actions don’t simply stop or come to a dead end; they produce a ripple effect of reactions. And this becomes painfully clear when we start to look at the subject of sin.

Before we go any further, let’s make sure we understand what sin is, exactly. It is the failure to live up to God’s perfect righteousness. Anything God wouldn’t do is sin. Anything inconsistent with God’s nature is sin. Anything less than pure holiness is sin. In other words, sin is something we continually struggle with as human beings, and we need God’s constant help to overcome its power in our lives (Galatians 5:16).

But when we do commit an act of sin, there are inevitable reactions. Something else happens that wouldn’t have happened otherwise—consequences that incur a cost! For example, look at David’s life in the Bible. While David is identified as a man after God’s own heart (1 Samuel 13:14), we know he wasn’t a perfect man by any means. He had his fair share of failings, and none are more prominent than his adulterous relationship with Bathsheba.

God’s Word tells us David did three things he never should have in regards to Bathsheba.

First, he saw Bathsheba bathing naked upon a rooftop. This was not an accidental glance or passing glimpse. The Scriptures tell us she was “very beautiful to behold” (2 Samuel 11:2 NKJV). David lingered in looking at something he shouldn’t have, and that’s often how sin starts in our lives.

Next, he coveted what he saw. David wanted Bathsheba for himself, even though when he inquired he was told she was another man’s wife. The very notion of wanting her for himself was off limits based on the Tenth Commandment—“You shall not covet your neighbor’s wife” (Exodus 20:17 NIV). Unfortunately, he allowed the seed of covetousness to grow.

Finally, he took what he saw and coveted for himself. There’s no way to sugar coat it: David used his power and prestige as king to coerce Bathsheba to have sex with him. It was a clear-cut violation of God’s heart for human sexuality as well as marriage . . . a sin if there ever was one.

There’s an interesting footnote which tells us that immediately afterwards, Bathsheba “returned to her house” (2 Samuel 11:4 ESV). It conveys that David and Bathsheba thought things would go back to normal, that they’d just get back into the routine of daily life. No harm done, right?

But Newton’s Third Law kicks in. The act of adultery produces a reaction. Bathsheba becomes pregnant with David’s child. He reacts to this by orchestrating a romantic evening between Bathsheba and her husband. Oh by the way, her husband, Uriah, is a loyal soldier in David’s army. And guess what, he doesn’t sleep with his own wife out of respect for his fellow soldiers back on the front lines!

David reacts again the next night. Only this time he gets Uriah drunk to lower his sense of honor. But Uriah unknowingly sidesteps David’s plot to pin Bathsheba’s pregnancy on him.

Frustrated, David reacts in a manner of last resort. He secretly orders his captain to put Uriah in a vulnerable position during battle so he will be killed. This is exactly what happens as Uriah dies. From David’s standpoint, the mission is accomplished. His sin with Bathsheba can be covered up now without any interference. David even marries her in order to make it all legitimate and put the whole thing in the past.

Except the exact opposite happens. We see yet another reaction. This time, God gets involved. He wasn’t going to allow this sin to go unpunished, and He confronts David with his sin through the prophet Nathan.

David repents, to which Nathan tells him God would forgive his sin. But that doesn’t mean the equal and opposite reactions of his sin would go away; that doesn’t mean there wouldn’t be any consequences. There were definitely consequences to be endured. Not only did David’s sin give the enemy ammunition to blaspheme the Lord’s name, but also the child Bathsheba would bear by him would not live.

Do you see how one act of sin produces a chain reaction where sins compound and do more and more damage, even to innocent bystanders? We need to understand this, because it needs to be part of our thought process before we act on our sinful impulses! We need to consider sin’s consequences—to ourselves and others—before we do what David did.

Imagine you’re David for a moment, and you’re right there at the “seeing stage” of sin. Only you see something in addition to Bathsheba. You see the deception, devastation, and death that’s to come. Do you think it would still go down the way it did? Or do you think it might have changed things and prevented all the tragedy that would follow? Do you think that awareness would help shift the balance from sinfulness to righteousness? And won’t that produce a far different, and better, series of reactions? Of course it would!

What’s done is done in David’s life . . . but not ours. Our lives are still being scripted, and we can influence how they read by realizing the real-life connection between our sin and Newton’s Third Law. We can consider the consequences before they come to pass.

We can even take it a step further and choose to take the right actions, what Jesus would do, which will produce righteous reactions! Instead of living for our own self-interests, we can see life as a series of opportunities to influence others for a greater good. This is the kind of lifestyle Paul describes in his letter to the Corinthian Church: “You say, ‘I am allowed to do anything’—but not everything is good for you. You say, ‘I am allowed to do anything’—but not everything is beneficial. Don’t be concerned for your own good but for the good of others” (1 Corinthians 10:23–24 NLT).

Newton’s Third Law doesn’t have to work against us. It can actually be a powerful ally in fulfilling our mission to be salt and light in this world. The difference comes down to the actions we decide to take, knowing they will produce a reaction . . . one way or another!

About the Author

Pastor Dan Hickling

Pastor Dan Hickling serves our online community, also known as the Calvary Chapel Online Campus. He and his wife Becky have been married for 22 years and have two children, Lauren and Danny. Both Dan and Becky have been part of the CCFL church family for 22 years and have served in full time ministry for 20 of those years.