With his hit singles of the '70s, Al Green proved again and again that he is one of the greatest singers of his time. Monday night at Constitution Hall, he proved that his gift has not diminished since he left pop music to preach and sing the gospel three years ago.

He now sings nothing but traditional hymns, but he delivers them with the rocking rhythm and sensual singing of his old hits. Though the subject has changed from physical love to religious faith, Green still brings more honest emotion to the surface of his voice than most singers even strain for.

Backed by a solid gospel-soul septet (including three pounding keyboards), Green employed all the squeals, grunts, whispers, shouts and purrs of his old repertoire in the service of the Lord. At one point he backed off from the microphone and shouted gruffly, determinedly, "His name is . . . ," paused just long enough and hit a pure, exhilarating falsetto note: "Jesus!" Later he broke into wild, improvised scatting that captured his indecision about conversion, and when he exclaimed "I Can't Turn Around," there was no doubting that it was a hard-won claim.

Gospel legend Shirley Caesar has a spectacular voice, but lacks Green's art. She is so convinced of her faith and preaches it so incessantly that she never allows the drama and revelation of Green's emotional confessions. Washington's own Genobia Jeter opened the show with the good instinct to build each song slowly to a crescendo, where she could let her gigantic voice go.