Last week, our country came together to honor a great man, and a great calling. The man was my husband, Sen. John McCain. The calling is serving a cause greater than ourselves.

This was the essence of John McCain’s message to our nation: that we must join together, shaped by our deepest values of liberty, equal justice and respect for the dignity of all people, hardened by unwavering courage and integrity, and step into the arena to fight for a greater cause.

John did this every day. Whether it was to demand the best possible leadership and support for our armed forces, or to empower freedom fighters against dictators around the world, or to demand that perpetrators of torture and human rights abuses be punished, or to make sure our native American communities are treated with dignity and respect. John McCain fought for others every day of his life, whether he was wearing a uniform or standing on the floor of the U.S. Senate.

John’s memory inspires me to be in the arena every day. Thank you for all the kind messages about my husband. I am grateful. Since his passing, thousands of people have asked how they can do something to honor Sen. McCain. I’ll tell you how: Join me in the arena. Fight for a greater cause.

The McCain Institute for International Leadership is now my home, and my mission. Through the McCain Institute, we will fight for all those values that animated my husband throughout his life. With your support we will pay his legacy forward.

I urge you to support the McCain Institute, and join me in the arena.

Cindy Hensley McCain is a trustee of the McCain Institute.

Read the article in USA Today here.