Freedom. Equality. Both are cornerstones of our treasured American heritage as well as primary foundations of Sikhism. The South Asian faith preaches equality among races, genders, and classes and incorporates this teaching in all aspects of its practice.

The Sikh temple, or gurdwara, which means "House of God," is open 24 hours a day, seven days a week, and has four doors pointing toward the four cardinal directions to welcome people from all faiths, creeds and backgrounds, demonstrating Sikh ideals in its very architecture.

You find this not only in India -- where the most notable of gurdwaras is the Golden Temple -- but also right here in the United States. In fact, you'll find it at the gurdwara in Oak Creek, Wisconsin, where one of those doors that welcomes all comers was used by someone who did not have equality in his heart.

Those four doors were kept open in no small part because of the tireless dedication and efforts of the president of the temple, Satwant Singh Kaleka, a personal, family friend I had the pleasure of knowing since we first welcomed members of his family to southeastern Wisconsin over 30 years ago -- a place that I still proudly call home.

Although we now know him as a victim of this horrendous act and as the hero who died trying to stop the gunman, I remember him as someone who never missed an opportunity to open his heart to you and greet you with a smile. And what a characteristic and beautiful smile it was.

His whole family is a fixture in the Milwaukee area and members carry with them that same spirit of love and caring. Indeed, one of my fondest memories is of Mr. Kaleka's family joyfully leading a group of guests in song at our home in Wisconsin the day after our wedding. So full of life.

Fate intervened and my family and I did not attend services that Sunday. The loss of our friends is deep and saddening and it hurts. But the effect it's had on not just the Sikh but the broader community has been nothing less than profound. And for that, in the midst of this grief, I am sincerely grateful.

In Sikhism, all are welcome and are one, without condition or limitation. All Sikh houses of worship have a community kitchen, called a langar, so that anyone in need of food can come and eat free of charge at any time. Indeed, tradition dictates that everyone who participates in langar sit at an equal level with all other diners to remind congregants to practice what is preached -- that we are all one.

Both at langar and elsewhere, congregants strive to serve others, especially those less fortunate. It's a practice known as seva, selfless service, and it represents the highest ideal and function of Sikhs.

At their core, the teachings and traditions of Sikhism represent the very best of what our beloved country stands for: a place of equality and opportunity open to and in service of all. And, as they've done in both in their home country and here in the United States, Sikhs have sacrificed greatly to ensure that this freedom is guaranteed to all.