"Judaism is much more concerned with actions than thought"
This is at best an out of context understanding and at worst a complete distortion of the Jewish faith.
"Service of the heart" is the core obligation of Judaism. Every single morning and evening Jews say the Shma which states the primary commandment of Judaism is to "Love G-d with all your heart, all your soul(personality), and all your resources..."
Maimonides has his twelve tenants of faith, which are all about belief and not at all about action.
Love and Faith are about connecting with and understanding G-d.
All the actions and commandments are tools for reaching spiritual connection and understand G-d with more clarity.
It is almost entirely a spiritual based faith...
The quote you reference, which for the life of me, I cannot recall as being accurate...certainly only means that behavior can influence belief.
We can form habits by behaving a certain way and we can come to believe certain things that are consistent with our behavior...The idea that Judaism is more concerned with action over thought is patently FALSE!
That being said, you can make the argument that some Jews today are more concerned with aesthetics than with true belief...but that is a shortcoming in their faith, and hardly a representation of what Judaism or the Torah teaches.
All that being said, a well rounded, Torah observant Jew, regardless of their denomination will have a healthy balance of faith, moral compass, and action that leads to living an optimal, healthy, happy, meaningful life to the fullest.
