Are you in spiritual danger? If you were, how would you know?

One key sign of spiritual danger is losing your joy. Don’t skim past what Paul says at the end of Philippians 3:1: “Finally, my brothers, rejoice in the Lord. To write the same things to you is no trouble to me and is safe for you.” Paul reminds them to rejoice because it is safe.

Joy is one of the vital gauges on the dashboard of the Christian life. When the needle dips — when you lose your joy — you should take note. To stay safe, you need to pay attention to your joy.

Life-and-Death Canaries

How does this work? Here’s an illustration.

Coal miners know that dangerous gases can gather silently and secretly in the tunnels. Carbon monoxide will asphyxiate them. Methane explodes.

A methane explosion took the lives of 12 men in the 2006 Sago mine disaster in West Virginia. In 1906, almost 1,100 miners were killed in Courrières, France in one massive chain of explosions.

“It’s hard for Satan to tempt a believer filled with joy in God with the empty pleasures of this world.”

But in the early days of coal mining, they found an effective, low-tech solution: They brought canaries into the mines. A canary’s metabolism is very sensitive to air quality. As long as the bright yellow birds chirp and sing, miners know the air is safe. If gas levels rise, the canaries stop singing, wobble on their perch, and eventually fall to the floor of the cage.

Christian joy is like that singing, yellow bird. One of the first effects of sin or doctrinal error is that we lose our joy in Christ. When your heart stops singing, that is a warning to watch your life and doctrine closely.

Jesus’s Joy in You

Jesus himself connected our daily spiritual life with joy.

“If you keep my commandments, you will abide in my love. . . . These things I have spoken to you, that my joy may be in you, and that your joy may be full.” (John 15:10–11)

If your soul is satisfied in Christ, you will rejoice in Christ. Take your eyes off Christ, and you’ll lose your joy. Christian joy is a barometer of your spiritual life.

Don’t confuse this unique joy with other upbeat feelings. Genuine Christian joy is not the power of positive thinking. Joy is not a bubbly, optimistic personality. Joy is not being happy because life is going my way. Joy is not walking through life with a naïve, glass-half-full attitude.

“The joy we have in Jesus cannot be extinguished by the circumstances of life.”

Jesus says it is my joy . . . in you. And Paul says, Rejoice in the Lord. Joy is the emotion of salvation. It is the joy of seeing, knowing, loving, and trusting Jesus Christ. We cannot generate this true joy ourselves — it is the product of the Holy Spirit in us (Galatians 5:22). Joy is a glorious gladness and deep delight in the person of Jesus Christ.

Such joy cannot be extinguished by the circumstances of life. It is a God-given joy greater and stronger than any trouble that comes into my life. As the prophet Habakkuk says,

Though the fig tree should not blossom, nor fruit be on the vines, the produce of the olive fail and the fields yield no food, the flock be cut off from the fold and there be no herd in the stalls, yet I will rejoice in the Lord; I will take joy in the God of my salvation. (Habakkuk 3:17–18)

As a spiritual barometer, joy is not a slave to circumstances. The light of Jesus’s face shines in the darkest night. Jesus said, No one will take your joy from you (John 16:22).

Joy Protects from Religion

How does Christ-gazing, Spirit-given joy keep us safe? Here are two ways.

First, joy keeps you safe as you serve. If you lose your joy, that could be a sign that your work for the Lord is no longer worship. Joy protects you from serving God for the wrong reasons.

George Müller was an evangelist and orphanage director in Bristol, England. He is famous for his tremendous faith and amazingly effective ministry — he cared for over 10,000 orphans over the course of his life. And joy was Müller’s first priority each day.

“Joy protects you from serving God for the wrong reasons.”

I saw more clearly than ever that the first great and primary business to which I ought to attend every day was to have my soul happy in the Lord. The first thing to be concerned about was not how much I might serve the Lord but how I might get my soul into a happy state, and how the inner life might be nourished.

Working hard for Jesus — even caring for thousands of orphans — is a cold and empty duty if we have lost the warmth of our love for Christ. Joy keeps you safe from serving as a religious duty.

Joy Protects from Temptation

Second, joy keeps you safe from temptation. Matthew Henry said, “Joy in the Lord will guard you from the empty pleasures the tempter uses to bait his hooks.”

Joy protects you because joy in Christ comes from being satisfied in Christ. I like what Jonathan Edwards says.

The enjoyment of (God) is the only happiness with which our souls can be satisfied. To go to heaven, fully to enjoy God, is infinitely better than the most pleasant accommodations here. Fathers and mothers, husbands, wives, children, or the company of earthly friends are but shadows, but God is the substance. These are but scattered beams, but God is the sun. These are but streams, but God is the ocean.

When I get up from the table after Thanksgiving, the last thing I want is more food. You can’t tempt me with another bite. In the same way, it’s hard for Satan to tempt a joyful believer with the empty pleasures of this world.

“Genuine Christian joy is not the power of positive thinking.”

A joyful believer is already more than satisfied in Christ — what more could he possibly want? Make it a point to be satisfied in Christ so that you rejoice in the Lord, and you will find safety and strength in your fight against sin.

Coal miners know that if the canary is not singing, there is trouble on the way.

So rejoice in the Lord! To write the same things is safe for you.