There are a few books out on the market that teach (solid) theology to children. Here are a few:
The Ology by Marty Machowski
This book is for younger children and it tackles breaking down the truths about Who God is and what He has done to redeem us into smaller concepts. The bonus for this particular book is it is beautifully illustrated in color. More details about the book here.
Big Truths for Young Hearts by Bruce A. Ware
This book, mostly geared toward parents of children 6-14, theology professor, Bruce Ware, attempts to simplify systematic theology so that parents can be better equipped to answer the questions of their children. More about the book here.
Big Truths for Little Kids by Susan & Ritchie Hunt
Big Truths for Little Kids is a devotional book written for ages 5-9 that follows the story of the sister and brother duo, Cassie and Caleb, as they discover truths about God. The book generally follows the outline of the First Catechism or Catechism for Young Children. Learn more about it here.
The links take you to different book seller sites. I've chosen to link to the one that has the lower list price. However, these books are available on all major book distributor sites if you want to bundle and save on shipping.
If you've ever lost vision temporarily in one eye, you know how frustrating it can be. Everything that came as second nature suddenly became more an exercise in active processing as your brain had to pick up on other data to determine your field of depth. Like many other things in life, we tend to take the importance of stereoscopic vision for granted, until it is gone. The same is true when it comes to two very important factors of the deepening of our walk with Christ and the deepening of our children's walk with Christ.