This Shabbos is called Shabbos Chazon, the vision. Named for the Haftora, the vision of Isaiah.
Our parsha starts with a rebuke of the Jewish people, Moshe lectures them on many of their failings. It ends, however, on a positive note. Moshe telling the, that when they enter the land and go up against Canaan, they should not fear, because HaShem will fight for them.
So too in the Haftora, Isaiah starts his vision with a rebuke, only to turn around and end on a positive note "Zion will be redeemed through justice..."
These readings are always read on the shabbos before Tisha b'Av, the fast of Av, the saddest day on the Jewish calendar. Commemorating the destruction of both our temples in Jerusalem and much more.
The rebukes found in our Parsha and Haftora seem to fit the theme of Tisha b'Av, but how does the positive ending fit?
It is for us to realize, that though Tisha b'Av is a sad day, all the sadness connected to it, has a positive purpose. None of the suffering was in vane.
Even more, we will see with clarity how our efforts and suffering, was that which accomplished the ultimate redemption.
This helps answer a second question.
When Moshiach comes Tisha b'Av will be celebrated as a happy day. Why? True all sadness will end, but it's history remains a sad one.
When Moshiach comes, Tisha b'Av will be celebrated as a happy day. Not merely because all sadness will end, but even more we will see the positive in all the Tisha b'Av events.
Each of us finds ourselves in difficult situations from time to time. It's hard to see the positive in it. But if you stop and recognize, that HaShem placed you in that specific situation, you will realize that there must be a positive purpose. Though you might not be aware of what the purpose is, you will be able to keep upbeat and positive.
Now with our soldiers fighting for the safety of our brothers and sisters in Israel we must be positive and do our part by adding in Torah, teffila (prayer), and tzedaka in their merit. Through this we merit the last words of our parsha "do not fear them, HaShem will fight for you".