Among the most powerful antidotes to both anguish and depression is a single word: Thank you.

What is the magic of gratitude?

Saying "thank you" implies two things: 1) I received something valuable from someone; and 2) it was generally something they were not obligated to give me.

What does this have to do with anxiety and depression?

One cause of anxiety is fear that things will not work out. When you express gratitude for something received, you affirm that you are not alone in the world. For things to go well, you don't have to rely only on yourself; there are others who have accompanied you in the past, and there is reason to hope they, or someone new, will do so again in the future.

One cause of depression is feeling unloved and unvalued. When you are grateful, you reaffirm that you received something from someone who cares about you. That, in turn, helps you care more about yourself.

In this week's Torah portion, Ki Tavo, we see how central a place gratitude occupies in Jewish life. The portion opens with the obligation to bring the first fruits of one’s fields to Jerusalem as a way of thanking G‑d for the abundance with which He has rewarded our efforts.

But there is an interesting detail: when the Jewish people entered the land of Canaan with Joshua, it took seven years to conquer it and another seven years to divide it among the twelve tribes. Rashi notes that the obligation to bring the first fruits — bikkurim — began only after the very last person had received their portion of land in the division.

Why did one have to wait for the last person to receive their portion before the first could bring their first fruits to give thanks and celebrate their own success?

The Rebbe highlights a deeply important lesson: until the last person has received their portion, there can be no complete joy — not even for the one who received theirs first. We are all interdependent. None of us can celebrate fully until everyone is in a position to celebrate.

Beyond the profound lesson in solidarity and responsibility for one's neighbor, there is also a practical tool for combating anguish and depression. One of the most reliable ways to find personal happiness is to invest in the happiness of others. To feel greater joy and satisfaction in your own achievements, help someone else achieve theirs.

The tool for this week: Say thank you often, sincerely, and with full awareness of what it means. And remember: your fullest joy depends, at least in part, on the joy of those around you.