Serve Adonai in fear/awe; rejoice with trembling. (2:11)
Fear and Trembling is an important work of philosophy by Soren Kierkegaard, using the model of the binding of Isaac to explore the meaning of faith. It is fundamentally a Christian look at the role of faith above all.
Judaism, which places action above faith, approaches this verse as instruction to serve God by observing mitzvot with fear and trembling, lest God withhold reward and send suffering upon the world. I’d rather focus on the second verb in the sentence which casts a different light on awe and trembling.
Picture a small child fully engaged by a movie, a storyteller, a performer of any kind – the wide open eyes, the open mouth. Such a child is fully open to anything that might happen. Her senses are totally focused on what is happening before her. At the climactic moment, her arms might begin to shake, her body might bounce up and down in her seat, giggles of laughter or shrieks of joy emerge from that open mouth, she might hug herself as if to keep herself from flying out her body!
That’s how I understand this verse – as a challenge to reach the highest level of focus, excitement, and joy while engaged in mitzvah. Could I reach that level of kavanah, intention, while shaking a lulav and etrog, while making Kiddush, while wrapping myself in tefillin, while delivering Purim baskets or doing some other act of gemilut hasadim? What an opportunity!