Job 31:29 New English Translation

²⁹If^[a] I have rejoiced over the misfortune of my enemy^[b]
or exulted^[c] because calamity^[d] found him—

Job 31:29 tn The problem with taking this as “if,” introducing a conditional clause, is finding the apodosis, if there is one. It may be that the apodosis is understood, or summed up at the end. This is the view taken here. But R. Gordis (Job, 352) wishes to take this word as the indication of the interrogative, forming the rhetorical question to affirm he has never done this. However, in that case the parenthetical verses inserted become redundant.
Job 31:29 sn The law required people to help their enemies if they could (Exod 23:4; also Prov 20:22). But often in the difficulties that ensued, they did exult over their enemies’ misfortune (Pss 54:7; 59:10 [11], etc.). But Job lived on a level of purity that few ever reach. Duhm said, “If chapter 31 is the crown of all ethical developments of the O.T., verse 29 is the jewel in that crown.”
Job 31:29 tn The Hitpael of עוּר (ʿur) has the idea of “exult.”
Job 31:29 tn The word is רָע (raʿ, “evil”) in the sense of anything that harms, interrupts, or destroys life.

New English Translation (NET)