It is not an action or a lack of action. It is an attitude. It is a feeling that if I do what God wants me to be doing then he will take care of the rest. But it is not a lack of action. It is a feeling that affects ones actions.
I discovered the book of Joseph Horowitz from Navardok. He holds from this type of trust in an undiluted way. And the fact that he does not dilute it is important.
[Now I think for this to be true to its purpose one has to be actively searching for God's will.]
This is one reason I have not written about this for years.
I admit to two things. First I fell from trust. I decided to leave Israel and go to Los Angeles and work and learn Torah on the side. What happened afterwards reminds me of a story in the Gemara of a friend of Rabbi Yochanan that did the same thing and lost his spiritual level. [The funny thing about this is that apparently working is fully in accord with the Shulchan Aruch.]
At some point I settled on the path of the Rambam/Maimonides in his combining learning Torah with Physics and Metaphysics as he calls them in the Guide for the Perplexed.
Well I was plenty perplexed, and this path of the Rambam made the most sense to me. So I went to New York and majored in Physics at New York University.
This is not a path that is commonly associated with trust in God but hey --it works for me.
Part of the reason I did not just fall back on the general chareidi [Ultra Orthodox] path is that I think that there is good and bad in the chareidi [Ultra Orthodox] path. It is not something I could put a stamp of approval on. Without the "Reason" of the Rambam, it lacks a self correcting mechanism.