The Baal Haturim noted that last week’s Parsha spoke of the נדרים ונדבות, the free will offerings. They were not offered on Yom Tov. The connection is that this week’s Parsha, מטות-מסעי, begins with making vows and their potential cancellation. If we look at the subject following this, the Torah speaks of taking revenge against Midyan, for their role in creating a plague that killed 24,000 people.
The connection between subjects, is that the Rabbis made an exception regarding vows. Normally, we say that it is far better not to make a vow, than to make a vow and not fulfill it. However, they also say, נודרים בעת צרה, that it is appropriate to make a vow in times of trouble, like a war.
It is fascinating to see the סמיכות הפרשיות, the connection between sections of the Torah. In this case, the common thread is that vows must be taken seriously. We must never go back on our word. If we say we are going to do something, we must do it.
The Rabbis emphasize this point by saying that for the sin of unfulfilled vows, one may be forced to bury his children. And this explains why the Kol Nidrei prayer of Yom Kippur has such great significance. How is it possible for us to ask for atonement for our sins, if we did not fulfill our vows, or keep our word.
It is so wrong to make promises to others that we do not fulfill. But, on the other hand, it is invaluable to gain a reputation of trustworthiness. It sets a great example to our children, when they see how well their parents are respected because of their honesty and integrity. Perhaps this is why the Torah gives so much emphasis on vows and keeping our word.