Using heavy paper and pictures of "Heaven," have the children construct a simple gate by gluing two vertical strips of paper and one horizontal. Put the picture behind it and have the children look through the narrow gate into Heaven.
If we've lived uncontrolled lives and walked on the broad path, we won't be able to squeeze into the narrow gate. We must try to live all our lives with strict adherence to the principles of Heaven. Have the children draw a picture of a winding narrow path going through dark woods with frightening creatures on both sides. Put a magnificent castle at the end of the path with a narrow gate.
Have the children cut out circles from heavy paper and glue them to the sides of something like a compact disc box. Have them practice driving the narrow car down a narrow path. Help them see that it takes a lot of care to keep the box upright and on the path.