There is an art to putting together a symphony program. And at this weekend’s Buffalo Philharmonic Orchestra concert, conducted by Music Director JoAnn Falletta, the components fit together beautifully.

Samuel Barber’s “Knoxville: Summer of 1915” unfolds in a kind of nostalgic, sepia haze. The soprano sings about lost childhood, and her parents, a time and a place that are gone forever. It is lovely but it hurts, too, a lot like the play “Our Town.” You think of the years passing, people you have lost.

Then comes Mahler’s Fourth Symphony, and it lifts you up. It has its drama and its clashes. In the second movement, you look death right in the face. But then comes the gloriously ethereal slow movement, and from there you soar into the last movement, a vision of heaven, with its song about saints and music and dancing and all the food you can eat, cooked by St. Martha herself. It’s childlike and silly at times but in its naivete it is such a statement of faith. And you leave Kleinhans Music Hall smiling, thinking, so this is what life is all about.

In other words, Barber looks backward on this life and Mahler looks forward to the next. It’s a great juxtaposition, and a wonderful journey. The audience Saturday applauded it with tremendous warmth.

The concert begins with a buzz. Ralph Vaughan Williams’ Overture to “The Wasps” – a BPO first, the program says – is eight minutes long and leaves you wanting more, it’s so pretty and vivid. The buzzing of the wasps, courtesy of the strings, is startlingly realistic, and the English folk melodies are a joy. There were nice notes from the horns and the woodwinds.

“Knoxville: Summer of 1915” also had its share of creative sound effects, fun to hear in pristine Kleinhans. Barber gives you the clang and wheeze of a streetcar, the horn of a 1915 automobile. He also suggests the vast, starry night sky, and the BPO and soprano soloist Heidi Grant Murphy communicated that vision with a natural, unhurried feel. The music had just the right gentleness.

Murphy sang very well, with sweet, clear high notes that you could tell would be great for the Mahler. But it was hard to understand the words she was singing. If you go to today’s concert, read the text in the program beforehand. If you don’t get to it, all is not lost – it’s easy, thanks to the music, to use your imagination. But the prose poem, by James Agee, is just so touching.

The BPO performed the Barber on its 2004 visit to Carnegie Hall. The orchestra is also, happily, no stranger to the Mahler.

Like the Barber, the symphony got a leisurely, loving performance on Saturday. Falletta gave it space and room to breathe. The sleigh bells, the triangle, the sharp blasts from the trumpet, the booms on the timpani – all the instruments were bright and distinct. Michael Ludwig, the concertmaster, put soul into the klezmer-ish, off-key fiddle solo in the second movement that suggests the dance of death. It was fun, by the way, to see Ludwig walk out with two violins, one in key, one out of key. What if he mixed them up?

Murphy’s voice is best in its highest registers. In her lower and middle range, it can be tough to hear her. There was one moment when she was drowned out completely by a honk from the bassoon. I bet Mahler, with his taste for the grotesque, would have liked that.

The last minutes of the symphony, so full of sighing serenity, drifted by with a lovely languor. The tender descending octaves just made you want to close your eyes, and now that I think about it, I imagine that must have been the composer’s intent. Dear Mahler. All I can think is he is up in heaven now, eating and drinking, with St. Martha waiting on him.

The concert repeats today at 2:30 p.m.