In Matthew 22:34-40 Jesus said that loving is the greatest commandment. What does this mean?

Here is the video of the sermon "More Than Words." Below the sermon video are the key points for further application.

More Than Words (part 1) from SOMA Church Community on Vimeo.

Sermon Application Points

1. To love God is to love him with our mind.
2. To love God is recall who God is and what he has done.
3. To love God is to obey him.
4. To love God is to evaluate and dianose our love for him (questions from Jerry Root).

• If Jesus came back at this moment would I be dissapointed?
• Can I say "thank you" in my present set of circumstances?
• Am I out of sorts with somebody?
• "Paul, do you love me?" (like Jesus asks Peter in John 21:15-19)