Centuries after the baroque masterpiece was composed, George Frideric Handel’s “Messiah” continues to inspire and uplift even those who have been performing it religiously every Christmas, like Steven Edwards, musical director for Symphony Chorus of New Orleans.

“We have performed ‘Messiah’ annually for nearly four decades,” Edwards said. “It is great to return to it every year. It’s like seeing an old friend who you haven’t seen for a while.”

Performing only two concerts, the 80-member SCNO, who will be accompanied by members of the Louisiana Philharmonic Orchestra, will perform the 1741 oratorio in almost its entirety at St. Mary’s Assumption Church, 2030 Constance St., at 7:30 p.m. Friday, Dec. 12, and at Holy Name of Jesus Church, 6367 St. Charles Ave., at 2:30 p.m. Sunday, Dec. 14.

The drama traditionally unfolds without elaborate scenery or costume, telling the story in a three-part structure of the birth of Jesus Christ, his sacrifice for humankind and his resurrection.

“It is not really about the history of Jesus Christ. It is about the mystery of salvation,” Edwards said.

Originally intended for an Easter performance, “Messiah” quickly found its place as a much-celebrated Christmas oratorio. In its entirety, it’s more than two hours long. More commonly though, concerts feature the most renowned choruses, “Hallelujah” and “Amen,” as the LPO will be doing in a separate pair of shows: its annual “Baroque Christmas: Outside the Bachs.”

For those, the LPO is joining forces with the New Orleans Vocal Arts Chorus under the leadership of guest conductor and New Orleans native Patrick Quigley.

There will be two performances of “Baroque Christmas: Outside the Bachs”: one at First Baptist Church, 5290 Canal St. in New Orleans, at 7:30 p.m. Thursday, Dec. 18, and another at Church of the King, 22205 Little Creek Road, Mandeville, at 7:30 p.m. Friday, Dec. 19.

“ ‘Messiah” speaks beautifully to the birth of Christ and the drama that is that story. It is good theater,” said Meg Frazier, artistic director and conductor of New Orleans Vocal Arts Chorale who will be singing alto.

Honoring the traditional baroque ensembles, LPO and NOVA have a smaller lineup of musicians and singers then their usual full cast.

“We will be using a chamber choir of 48 singers because the LPO is using a chamber ensemble, which is more typical to baroque-sounding ensembles,” Frazier said.

LPO and NOVA will be performing selections from “Messiah” among other baroque-era compositions, including Charpentier’s Overture from “Te Deum” and Mozart’s “Excultate, jubilate,” along with several of Bach’s cantatas.

“(‘Messiah’) is broken up into these sections that makes it so easy to pull out and make these Christmas choruses,” Frazier said. “They have become so well-known and so repeatedly performed because they are fun to sing and choirs really enjoy it. Everyone from the amateurish church choir to professionally paid choruses can sing sections of ‘Messiah.’ ”

Handel took only three to four weeks to compose “Messiah”; centuries later, arrangements such as “Hallelujah” have become a permanent fixture in holiday concerts around the world. Frazier explains that although many choralists and musicians have been performing the music from an early age, it is not easy to master.

“It is very complicated music to sing. It has a lot of running lines where Handel extends out a word over several bars. It is very easy to oversing, but it’s marvelous music. It is challenging, expressive and rewarding,” Frazier said.

The churches where “Messiah” is set to transfix audiences are well suited, not only for the religious reflections, but also for the acoustics that accentuate the powerful and uplifting music. It’s a combination that brings a certain kind of magic to the holiday season that no composer has been able to duplicate.

“The whole thing is a work of genius. It is an amazing couple of hours of music,” Edwards said.