What is at the Core of Jewish Belief?

I - "Na-aseh v'nishmah" (Exodus 24:7)
"We will do and then we will understand."
(Spoken by the Israelite people at Mt. Sinai after receiving God's teachings)

We emphasize doing over believing:  Judaism is a system of behaviors:  religious responsibilities called mitzvot.  Only through doing mitzvot that have been handed down through the generations can we begin to understand their importance to our lives and our characters.  Because we are primarily a system of actions, we have a lot of flexibility when it comes to our inner life - thoughts, feelings, beliefs.

II - We believe that we grow and develop by focusing on our outer life (actions, words) which then shapes our inner character.

Our religion is, first and foremost, concerned with doing mitzvot because we feel that it makes us better people to focus on doing traditionally holy things than it does to be concerned with thinking the "right" thoughts.  We believe that the doing will lead to a positive effect on our thoughts, feelings and attitudes.

III - We live with holiness when our lives and environments are structured.

The first chapter of Torah talks about how the world was tohu va'vohu (chaos and disorder). Holiness did not enter the picture until God organized it and separated everything into its own category.

Many of our mitzvot involve the act of living structured lives (striving to live in the image of God who created through structuring and organizing):

Keeping Kosher: all about keeping meat products and the dishes and silverware used for them separated from milk products and their associated stuff - our tradition encourages us to be deliberate about how we eat.

Shabbat: Six days are for working and being productive and day seven is set aside for rest and special observance - our tradition encourages us to be deliberate about organizing, dividing and using our time.

IV - Before we do a mitzvah, we recite an ancient blessing that reminds us how we bring love and holiness into our lives by performing this traditional act.

Every b'rachah (traditionally crafted blessing) recited before a mitzvah includes the words:  "Blessed are you, Adonay (God/Source of Life/Holy One/Holy Unity) . . . Who makes us holy through the mitzvot."
This phrase:  "asher kidshanu b'mitzvotav" (Who makes us holy through the mitzvot) is a key to understanding the essence of Judaism.  We are uplifted toward the Holy and the Godly as we perform traditional Jewish acts and rituals.