The best $7.99 I’ve spent in the last three years was adding a pretty extensive (and expensive, as far as apps go) weather app to my phone. It’s very cool. And just so you know I’m serious, I’ll say it again: It’s very cool. (Pay no attention to what my wife says regarding this issue.)

While you can use it to get all kinds of maps and track all kinds of storms, the thing I love most about it is the way it alerts me if severe weather is coming. You can set static locations, like home and work, and any time a storm is moving toward those locations, I get an alert. But it also has a “follow me” feature on it that, when you enable it, will alert you to severe weather when it is moving toward your current location no matter where you are. I could be in Colorado and get an alert about weather moving toward our home in Tennessee. Or I could be driving through south Texas and get an alert about a storm that’s currently in my path.

What is the alert? Glad you asked. It’s a truly obnoxious sound that’s impossible to ignore—just the way I like it. That means my days of staying up all night watching for any approaching tornadoes are over. I know that my phone is going to scare me half to death at 3 a.m. if indeed I need to know something dangerous is coming our way.

This single app has enabled me to live in a more alert fashion to this particular aspect of my environment. And it strikes me that, as a Christian, there are several reasons why alertness must characterize our lives. That we cannot simply muddle our way day in and day out but instead must live with a greater sense of awareness as a result of our faith. Here, then, are three such reasons why the Christian must live alertly:

1. Jesus is coming back.

This is a really real thing. It could be today. Like now. Or now. Or now. Or maybe tomorrow. That’s kind of the point. After a series of parables, all centering on the return of Jesus and the proper and improper ways to prepare, Jesus summarized it like this in Matthew 24:42: “Therefore be alert, since you don’t know what day[s] your Lord is coming.”

It’s in a slight way like coming home from work everyday. Though they don’t do it as often as they used to, occasionally I am greeted by the sound of my kids yelling to welcome me home when I come in the door. They didn’t know exactly what time I was coming, but they knew I was. And they were alert to my inevitable appearance. In the same way, we live with an uncertain confidence in Jesus’ return. We are confident that it’s happening, but not confident as to when. The proper response is to not make predictions around the exact time, but rather live constantly with a sense of alertness as to the inevitability of His impending return.

2. Opportunities are all around us.

The Christian must also live alertly because of the opportunities around us to make much of the kingdom of God. In the book of Ephesians, Paul lays out in two specific verses the rationale behind this. First, in Ephesians 2:8-10, he reminds us that we are saved by grace alone through faith alone in Christ alone, but he goes on to help us see that this faith is active in nature: “For we are His creation, created in Christ Jesus for good works, which God prepared ahead of time so that we should walk in them.”

God has saved us, but He has also intentionally planned good works for us and placed them in our path. These are good works we are to walk in, recognizing them as such, and then doing what the love of Jesus compels us to do day in and day out. That’s the heart behind the second verse in Ephesians, this one coming from chapter 5: “Pay careful attention, then, to how you walk—not as unwise people but as wise—making the most of the time, because the days are evil.”

Be careful, Christian, as you are walking, because unless you are alert, you will miss the opportunities right in front of you to work and invest for the sake of the gospel and the kingdom.

3. We have the tendency to drift.

We must, as Christians, be alert because Jesus is coming back. And we must be alert because of the opportunities God has put in our path. We must also be alert because we know our own hearts, and unless we are alert, we will always tend to drift from Jesus: “We must, therefore, pay even more attention to what we have heard, so that we will not drift away” (Heb. 2:1). No one drifts toward Jesus. Instead, like a boat not anchored in the middle of the sea, unless we are actively and alertly fighting against it, we will always move from our original position.

As we continue what discipleship means in the context of groups, one of the conclusions we must come to is that the maturing Christian is the Christian who is ever increasingly alert. We help people whom God has entrusted to our care to remember that Jesus is coming back, that opportunities around us abound, and that we all have the tendency to drift. May it be, then, that in all of our groups, as we continue to work toward discipleship, that we call one another day by day to a greater degree of attention.

Michael Kelley lives in Nashville, TN, with his wife, Jana, and three children: Joshua (10), Andi (7), and Christian (5). He serves as Director of Groups Ministry for Lifeway Christian Resources. As a communicator, Michael speaks across the country at churches, conferences, and retreats and is the author of Wednesdays Were Pretty Normal: A Boy, Cancer, and God; Transformational Discipleship; and Boring: Finding an Extraordinary God in an Ordinary Life. Find him on Twitter: @_MichaelKelley.