John Gill Commentary Psalms 70:3

"Let them be turned back by reason of their shame That say, Aha, aha." — Psalms 70:3 (ASV)

Let them be turned back for a reward of their shame
In (Psalms 40:15) it is, "let them be desolate"; which seems to respect their land and houses, here their persons; (See Gill on Psalms 40:15);

that say ;
in (Psalms 40:15) it is added, "to me"; not to his people, but himself,

aha, aha :
rejoicing at his calamity and distress. The Targum is,

``we are glad, we are glad;'' (See Gill on Psalms 40:15), and compare with this (Ezekiel 25:3) .