We have uniformly held that the language of a written contract, the terms of which are clear and unambiguous, governs the right and obligations of the contracting parties. Stratton v. Shaffer Oil Refining Co., 103 Okla. 28, 228 P. 772; Smith, Trustee, v. First Nat. Bank of Chandler, 114 Okla. 293, 245 P. 653, and Lee v. National Refining Co. et al., 181 Okla. 556, 75 P.2d 406. In the latter case we said:
In such case parol testimony is not admissible to vary the terms of a written instrument. Stratton v. Shaffer Oil Refining Co., 103 Okla. 28, 228 P. 772. We are unable to agree with defendant that the plaintiff was obliged under the liquidation contract to remain a party thereto until its claim was fully satisfied.
"A contract in writing, if its terms are free from doubt and ambiguity, must be permitted to speak for itself and cannot by the courts, at the instance of one of the parties, be altered or contradicted by parol evidence unless in case of fraud or mutual mistake of facts." Stratton v. Shaffer Oil Ref. Co., 103 Okla. 28, 228 P. 772. In the above case plaintiff sued on notes.
There was no condition attached to its delivery; and parol evidence that the accommodated parties assured appellant that he would never be required to pay the principal or interest of the note should not have been admitted. It tended to vary the terms of the written contract. ( Burke v. Dulaney, 153 U.S. 228, 14 Sup. Ct. 816, 38 L. ed. 698; Bank of California v. Starret, 110 Wn. 231, 9 A.L.R. 177, 188 P. 410; Would v. Hondins, 74 Colo. 400, 222 Pac. 404; First Nat. Bank v. Wolf, 208 Ill. App. 283; Stevens v. Inch, 98 Kan. 306, 158 P. 43; Stratton v. Shaffer, 103 Okl. 28, 228 P. 772; Brannan's Negotiable Instrument Law, 4th ed., 145 et seq., and note in 20 A.L.R., commencing at par. 421; Farmers' State Bank v. Farsstrom, 89 Or. 97, 173 P. 935.
"The execution of a contract in writing supersedes all the oral negotiations or stipulations concerning its terms and subject-matters, which preceded or accompanied the execution of the instrument, in the absence of fraud, accident, or mistake of fact; and parol evidence of representations made by an agent of the plaintiff prior to or contemporaneous with the execution of the written contract sued on, is inadmissible to contradict, change, or add to the terms of such contract." Inner Shoe Tire Co. v. Mueller, 108 Okla. 229, 235 P. 1072; Stratton v. Shaffer Oil Refining Co., 103 Okla. 28, 228 P. 772; Mitchell v. Williamson Motor Co., 108 Okla. 246, 235 P. 549. We do not consider the other errors assigned relative to instructions given and refused, as, upon a new trial being had, in conformity with this opinion, the alleged errors will not occur.