If you play nothing but the notes and chord highlighted by yellow in this passage from the “Haec Dies” Gradual, it’s quite ugly and dissonant. However, in the context of the stepwise descending bass-line, the LEMMENSINSTITUUT does not disappoint!
Pope Saint Paul VI (3 April 1969): “Although the text of the Roman Gradual—at least that which concerns the singing—has not been changed, the Entrance antiphons and Communions antiphons have been revised for Masses without singing.”