When God interacted with the Israelites in a way that was important for them to remember forever, they sometimes were instructed to built an altar or erect a pile of stones. For example, when Joshua led the Israelites across the dry bed of the Jordan River, he erected 12 stones as a memorial. Thus when their children asked the meaning of the stones, parents would be reminded to relate the account of God's miraculous deliverance from years of wandering through the desert.
When the Lord teaches us a valuable life lesson, we have an obligation to our children to pass this knowledge on to them. We share with our children the basics of our faith: praise God every day, even if you don't feel like it, because He is always worthy of praise. Thanksgiving opens our hearts and minds to receive the Lord's guidance and peace. Read your Bible and pray, because Scripture is living and active and you will find custom-tailored, Holy Spirit infused guidance for your life as You seek God in this way. Preach to the lost, but do not share camaraderie with them as one of them, or you will lose your own way.
These are the truths I've preached to my children over the years, and I am now blessed to see them implementing these basics of faith in their own lives.
But what about the times that God shakes us to our core with a revealed truth that is so astounding that we want our children to know and remember? I think we have an obligation to build some sort of a memorial. Some people scrapbook Scriptural truths into an heirloom that can be passed from generation to generation. Some embroider Scripture onto quilt blocks and create usable works of art that keep loved ones comforted physically and spiritually. An online blogger friend combines images from her collection of heirloom greeting cards with Scripture and hymns, creating beautiful, lasting works of art. I write books and blog posts.
When God speaks an important truth to your heart, don't keep it to yourself. Buy a pretty Bible and inscribe the thought on the frontispiece, signed Love, Mom (or Dad). Find an author that has expressed the truth and provide your children a copy of the book along with a personalized note from you. Take up quilting or scrapbooking, or record your own thoughts in manuscript form and publish them for free at Createspace. In this age, perhaps the easiest way to record the important things we want to pass along is through a blog, but keep in mind that we don't want to become too loquacious with the information we attempt to leave for progeny. With this in mind, I have one blog entitled "Just the Boldfaced Print" in which I record guidance I've received from the Lord, unmuddied by my own cogitations. Blogs can easily be made into books these days using a service such as BlogtoPrint.
Teaching our children the basics of the faith is probably enough of a challenge during their growing up years. But for grandparents I think it becomes especially important to give thought to the legacy we will leave behind. We have an obligation to our loved ones to share the comfort and instruction God has provided us.