Shared ground
Psalm 99:8 speaks to Yahweh as “our God” and recalls a remembered pattern: God answered when his people called, and his answer included both forgiveness and a firm response to wrongdoing. These are explicit claims in the verse, and they are presented together rather than as competing ideas.
The verse therefore links prayer and God’s response with God’s moral seriousness. Being heard by God is not depicted as God ignoring what happened; it is depicted as God staying engaged—restoring relationship while also addressing harmful actions.
Where interpretation differs
One main question is who “them” refers to. The closest names in the context are Moses, Aaron, and Samuel (v.6–7), but the verse could also be using those leaders as representatives for Israel as a whole.
Another question is what “vengeance” means here (Hebrew vengeance). Some take it as direct punishments God brought (for example, specific judgments in Israel’s stories). Others understand it more broadly as God’s corrective action and consequences that still follow sin, even after forgiveness.
Why the disagreement exists
The verse is short and does not specify the exact events behind “their doings,” and the pronoun “them” can naturally point either to the named leaders or to the people connected with them. Also, “vengeance” can describe either a targeted act of judgment or a wider pattern of retributive justice.
What this passage clearly contributes
This verse contributes a compact theological claim about God’s character and ways: Yahweh is responsive (“you answered”), forgiving (“you forgave them,” forgiving), and also a God who acts against wrongdoing (“you took vengeance for their doings”). It also contributes a key framing for prayer in Psalm 99: answered prayer is compatible with forgiveness and accountability, held together in the same divine response.