From the YouTube information:
“A Simple Song” is a hymn song from the musical theatre work composed by Leonard Bernstein with text by Bernstein and additional text and lyrics by Stephen Schwartz.
This Version is performed by Czech singer Jakub Hübner and it’s contained on Hübner’s album “Jakub Hübner” (2017).
Piano: Daniel Wunsch
Flute: Kateřina Macourková
Mix & mastering: Jakub Hübner
Photo: Denisa Grossová Photography
Graphic and video design: Jakub Hübner