One of the biggest reasons God gave us a family was to help us understand how He feels about us. He couldn't tell someone and have them write it as scripture in a way that would mean as much to us as letting us experience it ourselves.
Every father or mother I have asked says they can't describe in adequate words the way they feel about their children. Neither can our Heavenly Father. The way He loves us is like the way we love our children. Except it's perfect.
[ps. this video about made me cry... so good.]