Matthew 7:7 tells us, "Ask and it will be given to you; seek and you will find; knock and the door will be opened to you." It's an important message that sometimes bears repeating.

Lititz resident Mark Johnston has written a book that focuses on the importance of seeking God. It's titled "17 Cairns: Encounters and Reflections From a Lifetime of Following God's Trail."

"Ever since I was a little boy, I've had this desire to know God," said Johnston, a semi-retired physician. "The seeking, which continues, has brought me to where I am today. God reveals Himself to those who seek Him. He remains obscure to those who do not. God wants to have a relationship with us. He wants to have an intimate relationship with us."

"Whatever spirituality I have has come from the seeking," added Johnston. "God will reveal Himself to you to the degree you seek Him."

A cairn is a pile of rocks, and its uses include helping hikers navigate unfamiliar terrain. The spiritual interpretation of cairns refers to the moments in our lives when God reveals Himself to us through special life occurrences.

Johnston contends that life is filled with cairns, but he has identified 17 in his own life that have been profound or direction-altering. He said that all of us have experienced spiritual cairns, but some of them go unrecognized.

"We all have cairns in our lives, and sometimes when you read about other people's cairns you can see the ones in your life," said Johnston. "It's like what I've been called to do. It's like good news in another way. It's just another perspective on a truth that's been with us all along. If you recognize a cairn in your life, share it. There's something enriching about examining our lives."

Among the cairns Johnston explores in his book are a son's bout with cancer, the death of his father, his invention of a medical device used to treat conditions of the esophagus and dreams that feature out-of-body experiences.

"The things I've learned in life have taken a long time to learn," said Johnston. "The idea of a cairn at age 7 is a completely foreign concept. I had been in (medical) practice for many years when I recognized them as an adult later in life. The cairn thing was a slowly progressing, evolving idea over years. Now it's crystal clear."

After serving as a doctor in the United States Navy for 20 years, Johnston established a private practice in Lancaster in 2005. His life journey has taken him from Holland Patent, N.Y., to Penn State, Drexel Medical School in Philadelphia and now Lititz. Johnston has completed numerous medical mission trips abroad over the past three decades.

"I made myself more naked than I thought I would," said Johnston of the writing of "17 Cairns." "I made myself vulnerable. When I semi-retired, it allowed me time to write. I'm kind of at a time of peace in my life. I'm entering into a new season of my life. But I think there's been a little bit of wisdom that's been acquired over the years."

It took Johnston three years to write the book, his first.

To purchase a copy of Johnston's book, search for "17 Cairns" on Amazon.