"Dan will exact judgment for his people, the Tribes of Israel will be like one. Dan will be like a snake on the path, a viper on the way, which bites the heels of a horse causing the rider to tumble off backwards. For your salvation do I long, HaShem!" [49:16-18]
Dan is described as a protector of his people, and an extremely dangerous foe to his enemies. But immediately after saying so, Yaakov nonetheless declares -- "For _YOUR_ salvation do I long, HaShem!" Despite all of the protection that Dan or any human can offer, Yaakov always depends ultimately upon HaShem.
The Ba'al Shem Tov, literally "the Master of the Good Name," was the father of the Chassidic movement. Once, he sent two of his students to a distant country in order to procure wine for Passover. His students were anxious to please their teacher, so they made every effort to do the job right, to return with wine in which was unquestionably Kosher for Passover.
They went out to the vineyards, helping to select the best grapes. They meticulously supervised the pressing of the grapes to ensure that no grain products were anywhere nearby. They ensured that the wine was sealed in the strongest casks, which they then transported back under their constant supervision.
Immediately after their return, they unsealed the casks and tasted the wine -- and it was perfect. They briefly left the room to tell others that they had come back with wine which met the highest standards both in taste and in Kashrus supervision.
When they returned, they were greeted by a non-Jewish worker, chewing on a ham sandwich, who exclaimed, "that's delicious wine you have there!"
Of course, given the possibility that part of the sandwich had fallen into a cask, all was lost. The Ba'al Shem Tov would unquestionably not be able to use this wine.
With broken spirits they went into their teacher, to explain how the wine was lost in such a bizarre way. With penetrating insight, the Ba'al Shem Tov told them, "you did everything you could, everything possible, to guard the wine. You were so careful, in fact, that you forgot to ask G-d to watch over _you_. You left no place for His protection!"
There is a tension, as it were, between the concepts of "hishtadlus" and "bitachon," between our obligation to make an effort on the one hand, and our obligation to rely upon Divine Providence on the other. We must make an effort, and cannot stumble forward blindly. But at the same time, we must be careful to recognize that the ultimate success or failure of those efforts does not lie in our hands.
A perfect example, of course, is "making a living." We have to make an effort. But a leading Rabbi once commented that people come to him with all sorts of questions regarding how much we must do -- in other areas. How much wine must I drink for Kiddush? How much matzah must I eat at the Seder? How much money do I need to give to charity? And no one asks, "how much effort must I make at providing for my family?"
Even as we make that effort, we must remember that success is ultimately not ours to achieve -- and we must trust in G-d to give us what we truly need.