A Thought on Bitachon
From the shiurim on Kav Hashgacha Pratis
He Who Trusts in Hashem Will Not Fear, and He Will Be Saved
One who trusts in Hashem is so strong in his spirit that even in a time of danger he does not fear of beasts of prey. He relies on the Creator and will be saved from all dangers. It follows, therefore, that when dealing with important life-decisions, a person should not worry even if in his situation it seems that he will not be able to get anything for his sustenance. He should not fear in his heart at all, but rather should rely on Hashem with bitachon that he will get what he needs, for nothing is too difficult for Hashem to grant him. He should firmly believe that Hashem will provide his needs on the level that he has been accustomed to receiving, so much so, that it seems to him as though what he needs is already prepared and waiting in front of him, without forgoing anything of what he is accustomed to receiving.
(based on Madreigas Ha’adam, Darchei Habitachon)
One Who Follows the Torah Can Change What Has Been Decreed Upon Him
We need to believe that tefillos and zechuyos and tzedakos can change, to become good, what has been decreed upon a person according to the constellations, including from death to life, from pain to joy and from mourning to happiness, and much has been said about the virtue of this emunah...
(based on Beis Habechirah LaMe’iri, Shabbos 156)
They Lack Bitachon
Lo Senachashu – One should not make predictions based on superstitions, like those who predict things upon observing the behavior of rats or birds; or those who say, “Since his bread fell out of his mouth...,” or, “A deer crossed his path,” and they say, “This is a sign that I will not succeed,” and then they cancel their plans due to these “signs.” One may not use such superstitions to decide whether to do something or to refrain from doing something.
Lo Se’onenu – This refers to seasons and times, like someone who says, “This day of the week is a good day to start working”; “This hour is a bad time to go out...” Rather, your heart must trust in the G-d of the Heavens and the earth. That is why it says regarding this matter (Devarim 18:13): “You shall have perfect trust in Hashem your G-d.” We learn from this that fortune tellers and magicians are lacking in bitachon, and their deeds are the deeds of Canaan.
(based on Shaarei Teshuvah by Rabbenu Yonah, 3:86)