The reason for this command is given: We are not to swear “by the heaven, for it is the throne of God; nor by the earth, for it is the footstool of His feet; nor by Jerusalem, for it is the city of the great King. Neither shalt thou swear by thy head, for thou canst not make one hair white or black.”Matthew 5:34~36. R.V.
(MB 66.1)
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All things come of God. We have nothing that we have not received; and, more than this, we have nothing that has not been purchased for us by the blood of Christ. Everything we possess comes to us stamped with the cross, bought with the blood that is precious above all estimate, because it is the life of God. Hence there is nothing that we have a right to pledge, as if it were our own, for the fulfillment of our word.
(MB 66.2)
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The Jews understood the third commandment as prohibiting the profane use of the name of God; but they thought themselves at liberty to employ other oaths. Oath taking was common among them. Through Moses they had been forbidden to swear falsely, but they had many devices for freeing themselves from the obligation imposed by an oath. They did not fear to indulge in what was really profanity, nor did they shrink from perjury so long as it was veiled by some technical evasion of the law.
(MB 66.3)
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Jesus condemned their practices, declaring that their custom in oath taking was a transgression of the commandment of God. Our Saviour did not, however, forbid the use of the judicial oath, in which God is solemnly called to witness that what is said is truth and nothing but the truth. Jesus Himself, at His trial before the Sanhedrin, did not refuse to testify under oath. The high priest said unto Him, “I adjure Thee by the living God, that Thou tell us whether Thou be the Christ, the Son of God.” Jesus answered, “Thou hast said.”Matthew 26:63, 64. Had Christ in the Sermon on the Mount condemned the judicial oath, He would at His trial have reproved the high priest and thus, for the benefit of His followers, have enforced His own teaching.
(MB 66.4)
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