Excerpted with permission from Come Thirsty by Max Lucado, W Publishing Group, copyright 2004.

You're acquainted with physical thirst. Your body, according to some estimates, is 80 percent fluid. That means a man my size lugs around 160 pounds of water. Apart from brains, bones, and a few organs, we're walking water balloons.

We need to be. Stop drinking and see what happens. Coherent thoughts vanish, skin grows clammy, and vital organs wrinkle. Your eyes need fluid to cry; your mouth needs moisture to swallow; your glands need sweat to keep your body cool; your cells need blood to carry them; your joints need fluid to lubricate them. Your body needs water the same way a tire needs air.

In fact, your Maker wired you with thirst-a "low-fluid indicator." Let your fluid level grow low, and watch the signals flare. Dry mouth. Thick tongue. Achy head. Weak knees. Deprive your body of necessary fluid, and your body will tell you. Deprive your soul of spiritual water, and your soul will tell you.

Dehydrated hearts send desperate messages. Snarling tempers. Waves of worry. Growling mastodons of guilt and fear. You think God wants you to live with these? Hopelessness. Sleeplessness. Loneliness. Resentment. Irritability. Insecurity.

These are warnings. Symptoms of a dryness deep within. Perhaps you've never seen them as such. You've thought they, like speed bumps, are a necessary part of the journey. Anxiety, you assume, runs in your genes like eye color. Some people have bad ankles; others, high cholesterol or receding hairlines. And you? You fret. And moodiness? Everyone has gloomy days, sad Saturdays. Aren't such emotions inevitable? Absolutely. But unquenchable? No way.

View the pains of your heart, not as struggles to endure, but as an inner thirst to slake-proof that something within you is starting to shrivel. Treat your soul as you treat your thirst. Take a gulp. Imbibe moisture. Flood your heart with a good swallow of water.

Where do you find water for the soul? Jesus gave an answer one October day in Jerusalem. People had packed the streets for the annual reenactment of the rock-giving-water miracle of Moses. In honor of their nomadic ancestors, they slept in tents. In tribute to the desert stream, they poured out water. Each morning a priest filled a golden pitcher with water from the Gihon spring and carried it down a people-lined path to the temple. Announced by trumpets, the priest encircled the altar with a libation of liquid. He did this every day, once a day, for seven days. Then on the last day, the great day, the priest gave the altar a Jericho loop-seven circles-dousing it with seven vessels of water.

It may have been at this very moment that the rustic rabbi from the northlands commanded the people's attention. "On the last day, that great day of the feast, Jesus stood and cried out, saying, `If anyone thirsts, let him come to Me and drink. He who believes in Me, as the Scripture has said, out of his heart will flow rivers of living water'" (John 7:37-38 nkjv).

Finely frocked priests turned. Surprised people looked. Wide-eyed children and toothless grandparents paused. They knew this man. Some had heard him preach in the Hebrew hills; others, in the city streets. Two and a half years had passed since he'd emerged from the Jordan waters.

The crowd had seen this carpenter before. But had they seen him this intense? He "stood and shouted" (nlt). The traditional rabbinic teaching posture was sitting and speaking. But Jesus stood up and shouted out. The blind man shouted, appealing for sight (Mark 10:46-47); the sinking Peter shouted, begging for help (Matt. 14:29-30); and the demon-possessed man shouted, pleading for mercy (Mark 5:2-7).

John uses the same Greek verb to portray the volume of Jesus's voice. Forget a kind clearing of the throat. God was pounding his gavel on heaven's bench. Christ demanded attention. He shouted because his time was short. The sand in the neck of his hourglass was down to measurable grains. In six months he'd be dragging a cross through these streets. And the people? The people thirsted. They needed water, not for their throats, but for their hearts.

So Jesus invited: Are your insides starting to shrivel? Drink me. What H2O can do for your body, Jesus can do for your heart. Lubricate it. Aquify it. Soften what is crusty, flush what is rusty. How? Like water, Jesus goes where we can't. Throw a person against a wall, his body thuds and drops.

Splash water against a wall, and the liquid conforms and spreads. Its molecular makeup grants water great flexibility: one moment separating and seeping into a crack, another collecting and thundering over the Victoria Falls.