Q: What is the difference between being spiritual, ethical/moral and simply following the law?
A: In a word: motivation.
It gets to the "why" we do things rather than just be focused on the "how."
This is the very heart of what it means to be a Christian. We live out of a "core spirituality" rather than simply following a set of laws and expected behavior.
You can spend your life finding out all the behaviors, knowing all the rules, doing everything appropriately... and yet still not have your heart in it.
In other words, you're just going through the motions.
Christianity asks you to change your motivation from "I won't do this because I'll get caught" to "Because of God's love, how can I love others better?" and "What is it that God is calling me to do?"
This is what Jesus meant when he talked about "all the law and the prophets" being wrapped up in love. Such ethical and legal activity ultimately rest on the two great commandments: "Love God" and "Love your neighbor as yourself." (Matt 22:36-40)
So it comes down to "What motivates you?"
Are you doing something because the law says it's OK? ...something your friends, family and perhaps the society expects?
Or are you acting out of gratitude for the presence of God, Jesus Christ in your life?
The first case asks: "Will I get caught?" and "How do I become a good person?"
The second: "WWJD?" (What would Jesus Do?) or better yet "WWJHMD?" (What would Jesus have me do?)
To be spiritual means you have a foundation that comes from "outside" your own interests to base your behavior and your decisions upon. To be spiritual is to rely on, trust in, have faith in God as the one who gives your life direction and purpose.
All this is possible because of God's great love for us and God's willingness to be in our life with us.
All this is possible because of the great love and sacrifice given to us in Jesus Christ.