SOUTH END -- The Archdiocese of Boston's Catholic Lawyers' Guild and the Guild of St. Luke for healthcare workers will host guest speaker Kenneth Hackett, U.S. Ambassador to the Holy See, after a combined celebration of the Red Mass and White Mass Oct. 26 at the Cathedral of the Holy Cross.

According to Father Mark O'Connell, judicial vicar of the archdiocese and chaplain of the Lawyers' Guild, the Red Mass was rescheduled from its original Sept. 28 date to accommodate Hackett's schedule. Because Hackett was available around the time that the White Mass was originally scheduled, organizers agreed to a combine their celebrations to allow both groups to hear from Hackett at a luncheon after the Mass at the Seaport Hotel in Boston.

Before being named Vatican ambassador, Hackett, a West Roxbury native, served as president of Catholic Relief Services. During his tenure he oversaw CRS's response to the Rwanda genocide, the Bosnian and Kosovo emergencies, the Asian tsunami, the Haiti earthquake, and the HIV/AIDS crisis. He has also served as a member of the Global Poverty Task Force led by the White House Office of Faith-based and Neighborhood Partnerships, and in leadership and volunteer roles at other international and Church humanitarian, charitable, and foreign aid agencies.

A tradition dating back to the Middle Ages, the Red Mass seeks to invoke the guidance of the Holy Spirit for those in the legal professions -- traditionally judges, lawyers, attorneys, government officials, as well as students and teachers in the study of law. The red in the vestments worn by clergy symbolizes the fire of the Holy Spirit, and the Mass is traditionally associated with St. Thomas More, patron of lawyers, attorneys and civil servants.

The White Mass honors those who serve others in the field of healthcare -- doctors, nurses, technicians, and other healthcare professionals. The Mass is associated with St. Luke, patron of physicians and surgeons.

All are invited and encouraged to attend the Mass. The Lawyer's Guild is hosting the luncheon after the Mass. Tickets are available at www.clgb.org/events or by emailing info@guildofstluke.org.