Conductor Norman Scribner and his splendid Choral Arts Society observed Easter at the Kennedy Center Concert Hall yesterday with a suitably celebratory program. All three works were major religious compositions by major composers and all three are rarely performed.

Mozart's "Vesperae Solennes de Confessore" are not as solemn as the title implies. And Poulenc's "Gloria" is even more exuberant in its praise of the Lord. The third work, Benjamin Britten's "Cantata Misericordium," is less upbeat--it is, after all, a setting of the parable of the Good Samaritan.

One thing, though, that all three works have in common is that they are highly secular, by the standards of music for the church. And another common denominator is that all three are first-rate.

It comes as no news that the Choral Arts Society is a first-rate chorus that can handle anything, from the exquisite chamber music nuances in the Britten--it includes a string quartet--to the grand and Gallic urbanity of the Poulenc--and if you think urbanity and devoutness can't coexist you just haven't heard the "Gloria," or the great opera that Poulenc produced at about the same time, "Dialogues of the Carmelites."

So far as the four fine soloists were concerned, it was soprano Judith Borden's day. The high point of the Mozart is a serene aria set to "Laudate dominum." This is one of those works of heartbreaking simplicity--like the slow movements of his greatest concertos--that define what Mozart is all about. Borden's high voice, in particular, brought out this poignancy.

Poulenc's "Agnus Dei" is set similarly for the soprano. The worldly tranquility of this setting may seem a curious way to handle a text about so earthshaking a matter as the salvation of mankind, but with a voice like this its lyric understatement is meltingly lovely.

The Britten is, not surprisingly for him, as much a work of theater as of the church. Britten's theatrical instincts were so assured that he really couldn't have stifled them if he had wanted to. This fairly brief cantata, commissioned for the centenary of the Red Cross, came right after Britten's religious masterpiece, the "War Requiem." It is cut from the same terse, gorgeously crafted and ecstatic cloth. Baritone William Parker sang the part of the Traveler with great sophistication and intensity, and tenor Gene Tucker was memorable as the Samaritan.