This week remember to wish all your Muslim friends Ramadan Mubarak or Ramadan Kareem (“Blessed” or “Happy Ramadan”) as the annual fast of Islam commences.

Ramadan commemorates the month when the sacred scripture of Islam, the Koran, was given to the prophet Muhammad. In Islam, it is a period of purification, a time if fasting.

The fast is observed throughout daylight, commencing at sunrise and concluding at sunset each day. Not only does the fast include food, but water and other beverages— not even a sip. In many instances, Muslims even fast from most forms of entertainment, creating time to recite their scripture and performing additional prayers throughout the night (tarawih or taraweeh).

The fasting practice during Ramadan is not simply a fast from food, but a time of cleansing both the body and the soul. Even small children are included in this sacrament.

To Muslims, this practice is essential to their faith; Ramadan is one of the five pillars of Islam, the soul of the Islamic faith. Observing this fast is central to religious identity.

Sadly, it took me way too long to recognize a glaring inconsistency in my life. Every year at Christmas, I’d receive (and continue to) a flurry of well wishes from dear Muslim friends—all wishing me a “Merry Christmas.” Though many of my Muslim friends remembered me on many of the Christian holidays, I routinely failed to recognize theirs. The recognition of this religious holiday from so many Muslim friends always surprised me and their example has inspired me to be a better friend—their example has invited me into a new posture of solidarity that supports their own faith journeys.

I have since come to understand that Ramadan is not only a special time for Muslims, but for people of all faiths. For non-Muslims, we are invited to consider making our own sacrifices and we are challenged to follow the example of our devoted friends. This is a prayer time to consider what a more peaceful world might look like if we’d all prioritize periods of religious or non-religious purification.

So, this week, to honor your valued friendships with Muslims, I’d urge you to offer respect and affirmation by wishing them Ramadan Mubarak or Ramadan Kareem.

And, once the fasting has finished when the first crescent of the new moon is visible be sure to wish them Eid ul-Fitr Mubarak or Eid Mubarak to celebrate their devotion and sacrifices.

To all my Muslim sisters and brothers, may your sacrifice, example, and the fruit of your prayers bless us all and heal the world.

Note: a version of this post originally appeared July 12, 2012 as an oped piece for the Washington Post’s “On Faith.”