Editor's note: Pastor Kerry Shook and his wife, Chris, have four children and are founders of Fellowship of The Woodlands Church. This essay is an adaptation from their New York Times bestselling book, One Month to Live, (now available in paperback), which combines both their voices in one first-person voice.

I love watching my kids make sandcastles whenever we go to the beach. Now that they’re older, it doesn’t happen as often, but they used to sit for hours, digging and smoothing, shoveling and patting, trying to get the turrets just right, making a nice wide moat and then filling it from the ocean with their sand pails. I remember when they were really small how shocked they would always be as the tide started to roll in.  The waves would creep higher and higher until the foam began to lick the edges of their castle, and finally it was washed away. It took several attempts before my children realized their sandcastles were not permanent — they couldn’t last.

Unfortunately, I’ve witnessed too many people at the end of their lives feeling the same way. They work nonstop, ever busy with a hectic, overbooked schedule. Then eventually their bodies force them to slow down and take a look at what they’ve struggled so hard to construct. The harsh reality they often face is that much of what they strove for won’t last. After they die, it will wash away like a sandcastle at high tide.

Is the foundation for the castle you’re constructing made on sinking sand? If you truly want to leave an enduring legacy, one way to start is by grading the life you’re currently building in the following areas: influence, affluence, and obedience. As you read on, ask yourself: In which area do you struggle the most?  In which do you think you’re doing well? Are you pouring your most valuable resources into the investments with the greatest return: people? What would your life have to look like for you to achieve an A+ in each one?

Influence

You may have more or fewer opportunities than I have, but we all have been given a limited number of opportunities to influence others and make a difference in their lives. God has invested in each of us the ability to influence others, and He expects a return on His investment. He wants us to take advantage of our opportunities rather than burying our heads in the sand and ignoring our responsibility to make a difference in the lives of others.

Sometimes people are more concerned with making a name for themselves than making an impact on others. They think, If people know my name, then I’ll be significant and fulfilled. Abraham Lincoln wisely observed, “Don’t worry when you are not recognized, but strive to be worthy of recognition.” When we try to make a name for ourselves, it’s like writing our names in the sand. The waves of time will wash away everyone’s name, except for one — the name that’s carved in stone. The stone that was rolled away.  Philippians 2:10 tells us “that at the name of Jesus every knee should bow, in heaven and on earth and under the earth.” My life, my time, is not my own. It belongs to Christ, and it’s His name that will last; only when I live to influence others for Him will I leave an enduring legacy. You and I will be forgotten one day.  Only what we do for God, how we fulfill the purpose for which He made us, will remain.

Affluence

Not only must we pass the influence test to leave a lasting legacy, but we must pass the affluence inspection as well. If you’re going to have an impact on eternity, you have to consider how you spend your material resources. You may be tempted to think, Wait a minute, I’m barely getting by. I’m certainly not affluent! This must apply only to wealthy folks. I understand where you’re coming from, but with very few exceptions, if you’re reading this book, you’re considered affluent by the rest of the world.