I grew up with a fascination for sharks. Great whites, tigers, makos, and hammerheads—I love learning about them and talking about them. They fascinate me.

One dangerous shark you may not know about is the oceanic whitetip. It lives in the shallow zones of the deepest part of the ocean (known as the pelagic zone) and therefore isn’t encountered often by humans unless you have the misfortune of a shipwreck. It is known as “aggressively opportunistic” and takes advantage of fishermen’s catches or people abandoned at sea.

The whitetip hunts at a haunting pace, stalking prey in a way that makes its presence known. Given its deep habitat, there is nowhere to run. The whitetip approaches its prey methodically, tiring it out little by little, even taking small nibbles until the prey has no ability left to fight before devouring it.

It is more advantageous to attack when your prey is at its weakest.

This strategy is not unique to the whitetip, and it is certainly effective. When Jesus was in the Judean wilderness, He was at His humanly weakest. He hadn’t eaten in 40 days, and He was all alone. So the enemy took the opportunity to attack.

It often seems that our toughest challenges come when we are least equipped to fight them. When we are tired, stressed, and spread too thin—did I just describe you?—that is when we get hit with another curveball. This is not a unique experience for us, because we are at our most vulnerable in these moments, and our “aggressively opportunistic” enemy chooses these moments to attack.

Our enemy similarly stalks us from afar and approaches with small inconveniences—your headlight is out, the AC in your car is on the fritz—and then continues to build a mounting attack: your work schedule has changed and now it conflicts with your kid’s basketball schedule, and don’t forget to have the inspector come check that leak in the roof—until we start to crack.

Before you know it, the stresses are piling up, your attitude with your spouse is poor, and you snap at your kids for no reason. This is how the enemy wins—one bad moment at a time.

In these moments, our faith becomes imperative. In Jesus’ responses to the temptations of Satan, He consistently used one phrase over and over: “For it is written.” In other words, He used Scripture in His defense, relying on God’s Word to remind Himself where to turn in moments of weakness.

This is an example we must follow. Spend time in the Word and get to know God day by day. I pray you are able to hear His voice in your weakest moments and cling to those truths close to your heart. Our enemy is real—so too must our faith be!