Deuteronomy 19:13 uses the exact phrase 'purge the guilt of innocent blood from Israel', directly paralleling the command here.

Deuteronomy 19:12 shows the concrete action of handing over a murderer to the avenger, implementing the purge of innocent blood.

Deuteronomy 13:18 repeats the condition 'doing what is right in the sight of the Lord', the same standard for purging bloodguilt.

In 1 Kings 2:31, David orders Joab's execution to remove bloodguilt from his house — a direct application of the legal principle in Deuteronomy.

In 2 Kings 21:16, Manasseh fills Jerusalem with innocent blood, the opposite of purging it — showing failure to obey the law.

In Psalm 106:38, innocent blood pollutes the land — the same problem Deuteronomy 21:9's ritual aimed to cleanse.