There are very many who do not fear to deceive their fellow men, but they have been taught, and have been impressed by the Spirit of God, that it is a fearful thing to lie to their Maker. When put under oath they are made to feel that they are not testifying merely before men, but before God; that if they bear false witness, it is to Him who reads the heart and who knows the exact truth. The knowledge of the fearful judgments that have followed this sin has a restraining influence upon them. (MB 67.1) MC VC

But if there is anyone who can consistently testify under oath, it is the Christian. He lives constantly as in the presence of God, knowing that every thought is open to the eyes of Him with whom we have to do; and when required to do so in a lawful manner, it is right for him to appeal to God as a witness that what he says is the truth, and nothing but the truth. (MB 67.2) MC VC

Jesus proceeded to lay down a principle that would make oath taking needless. He teaches that the exact truth should be the law of speech. “Let your speech be, Yea, yea; Nay, nay: and whatsoever is more than these is of the evil one.” Matthew 5:37. R.V. (MB 67.3) MC VC