We raise our children to take care of books and not color in them.  So it was surprising for my kids to learn at an early age, that they could actually write/color in their Bible….with purpose, that is!  When they first received their chapter and verse Bibles, we also bought special Bible highlighters for them.    These were easier for them to use than underlining with pencil or pen.  Because I didn’t want them to go crazy with “coloring” or lose the highlighters, I kept them for them in a safe place.  

I’ll be honest and say that as the years have passed we haven’t been super consistent with marking all the verses that they’ve learned.  But, even with what we’ve done, it’s brought about the joy of familiarity with the Bible.  I remember as a child thinking the Bible was such a huge book!  However, the more I marked verses and wrote topics beside them, the more alive that book became.  Just as I did as a child, now my kids are also flipping through their Bibles exclaiming, “Oh, I remember when I learned that verse!”   

Those markings help that “Big Book” come alive!

You can tell from the markings in the picture, that it was from when my son was a preschooler. 
As your children get older, encourage them to also write topic words beside them.