Igros Moshe (YD 4:37:19) Even though a person has an obligation to have bitachon in G d and not worry about what will be tomorrow, that applies to his attitude concerning what has already happened. In such a case he shouldn’t lose his trust in G d since everything is from Him and He provides for everyone - He will surely send appropriate sustenance to the person and his family. In fact, however, a person must obtain a livelihood, food and all his needs as well as those of his wife and family not just for a single day but also for a long time by agriculture or business…
Chazon Ish (Ha-emuna Ve-ha-bittachon, beginning of chapter 2). . . an old error has become rooted in the hearts of many concerning the concept of trust. Trust . . . has come to mean that a person is obligated to believe that whenever he is presented with two possible outcomes, one good and one not, then certainly it will turn out for the good. And if he has doubts and fears the worst, that constitutes a lack of trust. This view of trust is incorrect, for as long as the future outcome has not been clarified through prophecy, that outcome has not been decided, for who can truly know God’s judgments and providence? Rather, trust means realizing that there are no coincidences in the world, and that whatever happens under the sun is a function of God’s decree.