It is now too late to be questioned, that if the holder of a promissory note, by a legal and binding contract with the principal, extend the time of payment beyond the day fixed by the note, without the consent of the surety or indorser, it is a discharge of the surety, at law as well as in equity. Boston Hat Manufactory v. Messenger, 2 Pick. 233. Gahn v. Niemcewicz, 11 Wend. 317. Clarke v. Henty, 3 Younge & Collyer, 187. 3 Stark. Ev. 1390, and note. The principle of this rule is, that by the enlargement of the time of payment, the contract is altered, the responsibility of the surety would be enlarged by it, and he has a right to say, that this is not the contract into which he entered.

But it was argued in the present case, that as the contract for enlarging the time was collateral merely, and would not bar an action, if brought after the day of payment and within the enlarged time, it did not affect the right of the surety. But the court consider that this would be too narrow a view of the effect of such contract. If the holder of the note has contracted to enlarge the time, he is bound by it; whether it is treated as a collateral undertaking upon which the legal remedy is to be sought at law, as in Dow v. Tuttle, 4 Mass. 414; or whether the remedy of the' promisor is in equity for a specific performance ; or whether the contract for an enlargement of the time of payment contains the stipulation, that, if violated, it shall enure by way of release ; it makes no difference to the surety. The holder of the note has a perfect right to enter into stipulations with the promisor, in regard to the time and mode of payment. Such stipulation, as between them, is a valid and binding con *179tract for further time, bearing directly on the contract, which he has no right to say, in an action against the surety, he did not intend to fulfil; and therefore the surety may avail himself of it, as a substantive alteration of the contract, and insist on his discharge.

Then the question recurs, upon the other part of the case, whether there was such a contract, in the present case, for enlarging the time. It appears by the verdict, that the jury, under the instructions given them, found that the plaintiff agreed with the promisor on the note, that if he would pay a part of the amount before the day of payment, he should have time, for a stipulated term after the day, for the payment of the residue; and that, in pursuance of this agreement, he paid the stipulated part, before the note was due. We concur in the opinion of the chief justice of the court of common pleas, that this was a promise made on a good consideration, and operated as a valid and legal contract for an enlargement of the time for payment of the balance. The payment of money before it is due is both a benefit to the creditor, and an inconvenience to the debtor ; and in both respects is a good consideration for a promise.

Another question arose, as to the competency of the witnesses. The objection to Goodwin, the principal promisor, is not now relied on; he being liable, at all events, for the whole. But the exception is to Gilman Dow, a co-surety with the defendant. That the fact, which he was called to testify, would, in a suit against himself, be a bar for him as well as the present defendant, is very obvious. But it is now well settled, whatever doubts may have been formerly entertained, that the interest, which renders a witness incompetent, is an interest in the event of the suit, and not an interest in the question. Bent v. Baker, 8 T. R. 27. Smith v. Prager, 7 T. R. 60. In the present case, the w itness was called by the defendant. But if the defendant succeeds in his defence, the verdict and judgment will be no bar in an action by the plaintiff on the same note against the witness. If the plaintiff recovers judgment in the present action, and obtains satisfaction, the defendant will, in addition to his remedy against the principal for an entire reimbursement, have an ac*180tion against the witness for a contribution, to the amount of one half the sum paid, exclusive of costs. But this liability would arise from the payment, not from the judgment. On the contrary, should the witness pay the whole amount, he would have the like remedy against the principal for reimbursement, and against the present defendant, his co-surety, for contribution ; and a judgment for the defendant, in this suit, would be no bar to such an action for contribution. It appears to us, therefore, that the legal rights and liability of the witness can in no way be affected by the event of this suit, and therefore that he was a competent witness. York v. Blott, 5 M. & S. 71.

Exceptions overruled.