Rashi, on Ps 52:1

“Unto the end, for Maeleth, understandings to David. The fool said in his heart: There is no God.”

“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.”

Imported from an open dataset — not yet checked against the printed edition.