Isaac is not the most aggressive figure in the Torah, nor even particularly proactive. In fact, Isaac spends most of his life reacting to what is going on around him. Given his life experiences, it should not surprise you to know that his relationship with God is described as "pachad yitz'chak," the "fear of Isaac."
We often use "fear" in relationship to God, but that is the kind of fear that is associated with awe – admiration, extreme deference, asense of being overwhelmingly impressed. The word for that kind of fear is "yir'ah," and we seek to discover it and then nurture it out of devotion.
But Isaac's fear is a different kind of fear – the kind you feel when you are on a dark road in heavy downpour, or when a stranger flashes a weapon, or when the return address on a piece of mail says "IRS." "Pachad" means anxiety as much as fear, and most of us try to avoid it, while the rest of us work hard to overcome it. So why do we include, in the opening words of our central prayer, a connotation that God is to be scary-feared instead of awesome-feared?
The title "pachad yitz'chak" is not a critique of God, but a statement about Isaac's life. While we associate him (and thus his fear) with the akeida, the binding for sacrifice, he encountered terrifying moments all his life: at the hands of his half-brother Ishmael, as he sought water and was chased away by local tribesmen, when he almost lost his wife to a rival tribe, and when he was deceived into giving away the blessing of the first-born to Jacob. Isaac was always afraid.
When my daughter Jennie was a little girl – perhaps seven or eight – we had a talk about faith I remember clearly. I asked her if she ever heard God. She thought for a minute and then said, "Yes, God talks in my heart." I asked her, "What does God say?" She replied, "He tells me not to be afraid."
That is the God of Isaac. Isaac knew fear all his life, but he never felt abandoned in that fear. The voice of God reassured him and stood with him through the moments that his heart sank and his knees knocked and his breath was hard to catch. Abraham's God of identity was at least as much external as internal, the self Abraham presented to the world. Pachad Yitz'chak was a more intimate and less public God. Each of us hopes never to need this relationship, but I suspect we are grateful to be reassured each time we pray that we need not worry that we will be alone when fear pays a visit.