I drive a SUV in Uganda, so when my sister’s boyfriend loaned me his diesel pick-up while I was in the United States recently, I thought I could manage it just fine. The very first time I put fuel in it, however, I made a big mistake: I topped off the tank with high-grade gasoline instead of diesel.

A string of unpleasant and expensive consequences resulted. First, I drove only 10 meters away from the gas station before the truck conked out. Then, an emergency road service had to haul the vehicle to a mechanic. To run again, the truck had to undergo an extensive detox that entailed siphoning the fuel and flushing the gas tank, hoses, filters, and injectors.

It was a costly mishap, but one that caused me to be more careful in selecting the type of fuel I put in vehicles. The incident also prompted me to consider the sources of strength (or weakness) that I allow to enter my heart.

In the Old Testament, God at times directed the use of unusual alternative energy sources that included “the wood of the Asherah pole” (Judges 6:26), “dried human dung” (Ezekiel 4:12), and even the plunders of war such as “small and large shields, bows and arrows, javelins and spears” (Ezekiel 39:9). A person’s emotional strength, however, came from things that brought comfort such as the birth of a child (Genesis 21:6-7), a visit from a beloved son (Genesis 48:2), or encouragement from a friend (Deuteronomy 3:28). Spiritual power, however, was derived from God alone—lest people took pride in their own “strength and energy” (Deuteronomy 8:17) and forgot that only the Sovereign Lord can perform “great and mighty deeds” (Deuteronomy 3:24).

Today, consider from where you derive your “fuel” and remember what Isaiah 40:31 says, “Those who trust in the Lord will find new strength.”

NLT 365-day reading plan passage for today: Acts 22:30–23:22