When I was in first grade, I had a teacher who would open every door while holding a handkerchief. Since the children had touched that doorknob before she went in, she was afraid of the germs and she would never use her bare hands, she would always use a handkerchief because she was afraid of the diseases that the children carry.
Now, if you think about it there are microbes, viruses, all types of tiny little things that we don’t see, yet we’re not afraid of them. We know that they can be very lethal; we know that people die all the time from illnesses and diseases, yet we don’t fear them. Why not? Because there’s a natural sense of trust that was implanted within me. Within me is a sense that I’m well, I’m healthy, and the current state will be forever.
The Chovos Halevavos explains that by nature we trust. If we didn’t by nature trust, then we’d be filled with fears, dreads, and the concept of obsessions and compulsions would consume all of us. Because the reality is there are a lot of bad things that could happen. There are a lot of diseases that infect people. Yet we have a natural sense of trust, we have a natural sense of I’m healthy, I’m well, and that will continue. And explains the Chovos Halevavos Hashem put that into the human being. By nature we trust. If we didn’t trust we’d be constantly filled with fear and dread.
Once I understand that by nature I trust, then it’s much easier for me to recognize that that which I trusted will eventually leave me, and it’s much easier for me then to transfer my trust from those things which are not reliable, to Hashem, which is the only reliable thing a person can possibly trust in.