It was a 20th-century Swiss theologian who came up with the delightfully succinct, and for him entirely appropriate, summation of the quintessential difference between two of classical music's greatest.
Karl Barth was explaining how he imagined things might sound in heaven. What the angels would play for their own amusement would be Mozart, but when it came to praising God, the music they'd perform would be Bach.
There could scarcely be two more contrasting characters. One was a child prodigy whose brilliance blazed from the moment he first appeared, a master of everything he'd turn his hand to. The other was industrious and prolific, but was never fully appreciated by the wider public until long after he was gone.
They were separated by 70-odd years. Johann Sebastian Bach was born in 1685; Wolfgang Amadeus Mozart in 1756.
Mozart was a freelancer, backing his talent to see him through, enjoying the challenge of coming up with new material to satisfy the demands of patrons and public.
Bach was like a 17th-century PAYE worker, hired by the authorities in Leipzig as the man who'd provide the soundtrack to Sunday observance in the city's four main churches.
Deadline-driven by the demands of the liturgical year, his was a musical production line that delivered score after score. Week after week, there would be new music.
Bach was in charge of the orchestra - professional players - and the choir for these performances. The singers were boys from the school where he juggled teaching duties alongside his composing commitments. There was never much space in his diary.
In his day, he was better known as an organist, the top man of his time. The counterpoint of his fugues and cantatas was no longer in fashion, it was too mathematically mechanical to the contemporary ear.
Even his composer son Philipp (CPE Bach) had a view that his music was rather old-hat. He and the family were less than assiduous in safeguarding their father's legacy. A lot of the scores were lost, somebody once unkindly suggesting many of the manuscripts had been used simply to light the fire.
So when a young Felix Mendelssohn - one of the few to appreciate the elder Bach's genius - decided to revive the St Matthew Passion in a performance that took place in Berlin on this date in 1829 - it was the work of a forgotten composer that he was staging.
It was the first time in over a hundred years that it had been heard, and it was only a truncated version that the 20-year-old Mendelssohn produced, but the impact was immense.
All of a sudden, Johann Sebastian Bach was flavour of the month. This man whose music had lain neglected for almost a century now had a public eager for more.
The famous Brandenburg Concertos - six pieces written for a patron whose house band wasn't big enough to play them - were finally published in 1850 to commemorate the centenary of Bach's passing.
Beethoven, who like Mendelssohn (and Mozart as well, to be fair), had 'got' Bach when musical fashion had consigned his output to oblivion, had been right all along. This music - too 'mathematical' in its time - had a lot more to it. Quite simply, said Beethoven, Bach was the forefather of harmony.
George Hamilton presents The Hamilton Scores on RTÉ lyric fm from 10am each Saturday and Sunday