Matthew 6:14-15 — is forgiving others necessary for salvation, or evidence of it?

Matthew 6:14-15 (Lord's Prayer context): "If you do not forgive others, your Father will not forgive you." Two possible readings: (1) forgiving others is evidence/fruit of being saved (parallel to 1 John's logic: loving God produces loving others); (2) inability to forgive represents an unrepentant heart that was never saved. Mike does not think the verse itself resolves the question — it is read through prior theological commitments. He leans toward it being an evidential marker, not a conditional requirement for justification.