Take no thought for the morrow. What?

In the Sermon on the Mount, Christ teaches, "Take no thought for the morrow, for the morrow shall take thought for the things of itself." 3 Nephi 13:34
This teaching is horrible. Of course we have to think about tomorrow and organize our lives around long-term goals—especially financial goals. We have to plan and count the cost of our plans and prepare for the future. If this teaching was taken at face value, it would mean that we should not even think about food storage.
As most teachings of Christ, looking at the surface can be misleading. So what did He mean by this teaching. If we look at the entire context, we learn that Christ is speaking specifically to the 12 apostles (verse 25). He is teaching them that they shouldn't worry about what to eat or drink, or about what to wear. The apostles shouldn't worry about these things because they will be taken care of by the Church. The apostles had a very specific task to do—teaching and managing the kingdom. They would be able to focus more on this job by not worrying about what they will eat.
In the latter days, when apostles are called, they quit whatever they were doing before. Apostles are full time. They are given a sufficient amount of money to live. They don't have to worry about money. The money given them does not come from tithing or fast offerings. It comes from the investments of the Church.
3 Nephi 13:34 has a very specific meaning to a very specific group. This is a good example of why understanding the context of a teaching is vital to its correct interpretation.