תהילים נג:א פירוש: רש״י

on machalath The name of a musical instrument. Another explanation: concerning the malady (מחלתן) of Israel when the Temple will be destroyed. He already recited another psalm resembling this one (above 14): “The fool said in his heart, ‘there is no God, etc.’ “, One relates to the destruction of the First Temple and this one, to the Second Temple.