Numbers 25:6-7

6And indeed, one of the children of Israel came and presented to his brethren a Midianite woman in the sight of Moses and in the sight of all the congregation of the children of Israel, who were weeping at the door of the tabernacle of meeting.

7Now when Phinehas the son of Eleazar, the son of Aaron the priest, saw it, he rose from among the congregation and took a javelin in his hand;