Deuteronomy 13:9

New English Translation

⁹Instead, you must kill him without fail!^[a] Your own hand must be the first to strike him,^[b] and then the hands of the whole community.

Deuteronomy 13:9 tn The Hebrew text uses the infinitive absolute for emphasis, which the translation indicates with the words “without fail” (cf. NIV “you must certainly put him to death”).
Deuteronomy 13:9 tn Heb “to put him to death,” but this is misleading in English for such an action would leave nothing for the others to do.

New English Translation (NET)