Deuteronomy 17:6 requires two or three witnesses for a death penalty, the same principle Paul applies to elders.

Deuteronomy 19:15 establishes the two-witness rule for any charge, directly underlying Paul's instruction here.

Matthew 18:16 has Jesus apply the same two-witness rule to church discipline, showing its continuity in the NT community.

John 8:17 records Jesus citing the same OT law that testimony of two people is true, affirming its validity.

2 Corinthians 13:1 has Paul himself invoking the same principle about establishing charges with two or three witnesses.

Numbers 35:30 establishes the multiple-witness rule for capital cases, a parallel OT legal standard for serious accusations.

Acts 25:16 ensures the accused faces accusers, a fair trial principle that parallels but is not identical to the witness rule.

Hebrews 10:28 recalls the OT penalty of death on two or three witnesses, highlighting the severity behind the principle.