To such purposes, therefore, oaths have ever been applied, as the most effectual instruments of working them; not only among the followers of true and perfect religion, but even among all those who had any glimmering notions concerning a Divine Power and Providence; who have deemed an oath the fastest tie of conscience, and held the violation of it for the most detestable impiety and iniquity. So that what Cicero saith of the Romans, that “their ancestors had no band to constrain faith more strait than an oath,” is true of all other nations, common reason not being able to devise any engagement more obliging than it is; it being in the nature of things τελευταια πιστις, and ουρωτατον αληθειας ενευρον, the utmost assurance, the last resort of human faith, the surest pledge that any man can yield of his trustiness. Hence ever in transactions of highest moment this hath been used to bind the faith of men.
Hereby nations have been wont to ratify leagues of peace and amity between each other (which therefore the Greeks call οοκια).
Hereby princes have obliged their subjects to loyalty: and it hath ever been the strongest argument to press that duty, which the Preacher useth, “I counsel thee to keep the king’s commandment, and that in regard of the oath of God.”
Hereby generals have engaged their soldiers to stick close to them in bearing hardships and encountering dangers.
Hereby the nuptial league hath been confirmed; the solemnisation whereof in temples before God is in effect a most sacred oath.
Hereon the decision of the greatest causes concerning the lives, estates, and reputations of men have depended; so that, as the Apostle saith, “an oath for confirmation is to them an end of all strife.”
Indeed, such hath the need hereof been ever apprehended, that we may observe, in cases of great importance, no other obligation hath been admitted for sufficient to bind the fidelity and constancy of the most credible persons; so that even the best men hardly could trust the best men without it. For instance,
When Abimelech would assure to himself the friendship of Abraham, although he knew him to be a very pious and righteous person, whose word might be as well taken as any man’s, yet, for entire satisfaction, he thus spake to him: “God is with thee in all that thou doest: Now therefore swear unto me here by God, that thou wilt not deal falsely with me.”
Abraham, though he did much confide in the honesty of his servant Eliezer, having entrusted him with all his estate, yet in the affair concerning the marriage of his son he could not but thus oblige him: “Put,” saith he, “I pray thee, thy hand under my thigh, and I will make thee swear by the Lord, the God of heaven and the God of the earth, that thou wilt not take a wife unto my son of the daughters of the Canaanites.”
Laban had good experience of Jacob’s fidelity; yet that would not satisfy, but, “The Lord,” said he, “watch between me and thee, when we are absent one from another. If thou shalt afflict my daughters, or if thou shalt take other wives beside my daughters, no man is with us; see, God is witness between thee and me. The God of Abraham, and the God of Nahor, the God of their father, judge betwixt us.”