Therefore if anyone is in Christ, he is a new creation. The old things have passed away. Behold, all things have become new. 2 Corinthians 5:17 web
However God’s firm foundation stands, having this seal, “The Lord knows those who are his,” and, “Let everyone who names the name of the Lord depart from unrighteousness.” 2 Timothy 2:19 web
A sealable plastic bag to keep new things fresh and ready to be eaten or used is very handy. One of these may be able to serve as a way of teaching children some concepts of the Bible that are not so tangible for them to understand. Try asking them if they would like you to put a snack into the bag and seal it up if it were all old and stale or even moldy. No! That would not be good. We want new and fresh snacks put into the bag and sealed to stay clean and fresh, ready to eat. You don’t want it to get dirty, dry out, or get stale.
Now the kids understand a tangible thing about what they want for their snacks and how a sealable plastic bag serves the purpose nicely. Now you may try applying the spiritual lesson. Like how we want our snack to be new and stay clean and fresh, God wants us to become a new creation and stay clean and fresh. That means He wants us to accept Jesus as our Lord and Savior to forgive us of all the bad things we do, then let Him help us to think and behave differently. Such as treating each other the way we would want others to treat us. Talking to God, spending time reading the Bible, and attending church help us to stay clean and fresh for God to use us. He enjoys using us to help others.