Have your family stand up with the goal of jumping as high as they can. Maybe have a goal on the wall or doorway or something to measure how high to jump. In the first situation, no one can bend their knees before they jump–not even a little! So basically you can only go on your tiptoes. You just can’t propel yourself into the air without bending your knees first. Next, have them bend their knees just a little bit and jump again. Notice how much higher they can jump. Then, finally allow your children to jump as high as they possibly can and bend as much as they desire.
Point out to them that the only way to reach and jump high is to bend low first. The Law of God shows us just how low we are compared to the righteousness of God. It takes that bending low to propel us higher. If we are brought low with who we are in our sin, then we can build sufficient faith and trust in God so he can lift us to a higher spiritual place. We have a greater understanding of just how powerful the "Grace" of Jesus Christ really is.