Va. Code § 49-29: Failure of principal to offer to defend suit against surety

In all cases in which any principal debtor, or his committee, representative or heirs, knowing of the pendency of any suit against his surety, or the committee, heir or personal representative of such surety, shall not offer to defend such suit, he shall be precluded from making any defense to the claim of the surety which he might have made against the suit of the creditor.Code 1919, § 5778.