"Not only his Masses, his Te Deum, his devotional choral works, but his symphonies also (and these before all) sprang from this fundamental religious feeling that swayed Bruckner's entire spirit. He did not have to struggle toward God; he believed. Mahler sought God. ... Bruckner sang of his God and for his God, Who ever and unalterably occupied his soul. Mahler struggled toward Him." Bruno Walter on Bruckner and Mahler
"The coda to the first movement is how it is when one is on his deathbed, and opposite hangs a clock, which, while his life comes to an end, beats on ever steadily: tick, tock, tick, tock, while in the slow movement I have gazed too deeply into a maiden's eyes." - Bruckner on his 8th symphony
Here's the Spotify playlist: Bruckner: Celibidache & MPO (58 tracks, total time: 15 hours) It includes all the officially released Bruckner recordings of Celibidache and his Munich Philharmonic Orchestra.