Yaakov Avinu sent Yosef to check up on his brothers in Shechem, but he didn't find them there. It states (37:15) תעה והנה איש וימצאהו בשדה, "a man found [Yosef]... straying in the field," and he directed him to his brothers. Chazal (Bereishis Rabba 84:14) tell us that a malach found him and showed him to his brothers. Actually, three malachim. The Midrash states וַיִּשְׁאָל ֵהוּ ,אִישׁ וַיִּמְצָא ֵהוּ ,לוֹ נִזְדַּוְּגוּ מ ַלְא ָכִים שְׁלשָׁה הָא ִישׁ וַיֹּאמֶר ,הָא ִישׁ. It states איש three times, to tell us that three malachim came to help Yosef find his brothers.
The Ramban writes, "This teaches us... that Hashem's decree is truth, and hishtadlus is false." This means that when something is bashert, it will occur, and there isn't any hishtadlus to do to prevent it from happening. It was bashert that Yosef be sold to Mitzrayim, and Hashem made sure that His plan would occur. If it weren't for these malachim, guiding him, Yosef would have returned to his father, saying that he couldn’t find his brothers. But Hashem's plan will always occur. When necessary, He sends a malach, or three malachim, to direct the person to where Hashem wants him to be.
The Ramban writes, "HaKadosh Baruch Hu arranged someone to direct him... so he would fall into their hands. This is Chazal's intention when they say that the איש in these pasukim refers to malachim. [It is to tell us that Hashem's plan will transpire.] The Torah wouldn't tell us this story for no reason. Rather, it is to tell us תקום היא 'ה עצת, Hashem's plan will transpire."
Rabbeinu Avraham ben HaRambam (on the Torah, 37:13) writes that Yaakov Avinu was always cautious to protect his son Yosef, so that he wouldn't be with his brothers alone. He knew what his other sons thought about him, and he suspected that they might harm Yosef, chalilah, when they are alone with him, and no one would know... However, it states in Mishlei (21:30) עצה ואין תבונה ואין חכמה אין 'ה לנגד, "There is neither wisdom or understanding nor counsel against Hashem." When Hashem wanted to have Yosef sold to Mitzrayim, Yaakov forgot to be cautious and sent Yosef to his brothers.
The Torah tells us that the brothers showed their father Yaakov the blood-stained clothing of Yosef, and he understood that wild animals killed Yosef (see 38:31-34). The Rebbe of Radzimin zt'l (Bikurei Aviv) asks, "Why did the brothers need to show Yaakov the blood-stained coat? Wouldn’t Yaakov understand on his own that if Yosef wasn't coming home, it means he was killed?"
He answers: The brothers were afraid that without seeing the blood-stained coat, Yaakov’s bitachon that Yosef would eventually return home would draw Hashem's aid, and somehow Yosef would come back. "The Mitzrim would surely send Yosef home. And then, Yosef would reveal to their father that his brothers sold him, and Yaakov would be angry with them. Therefore, they slaughtered a goat, dipped Yosef's coat in its blood, and sent it to their father."
From this vort we learn the tremendous power of bitachon!
The Chashmonaim won the war against the Yevanim because they trusted in Hashem. The Chashmonaim were kohanim, and כהן is gematria בטחון.
This can explain the custom of saying יושב עליון בסתר (Tehillim 91) after lighting Chanukah lecht. This chapter discusses bitachon. 'ה אתה כי מחסי, "You Hashem are my shield. תירא לא לילה מפחד, therefore I am not afraid.” It was with bitachon that they won the war against the mighty Greek army.
Avudraham writes that we don’t find the letter 'ז in this chapter because when one trusts in Hashem, he doesn’t need זיין כלי, weapons.
