A verb (שבע), signifying to swear, and two corresponding nouns are derived from a word for the number seven. That was a sacred number, or a number of perfection, not merely among the Israelites, but among other nations, and was used for the purpose of signifying an oath. A present of seven vouchers sometimes accompanied the act of swearing. "Abraham took sheep and oxen, and gave them unto Abimelech: and both of them made a covenant. And Abraham set seven ewe-lambs of the flock by themselves.—And he said, For these seven ewe-lambs shalt thou take of my hand, that they may be a witness unto me that I have digged this well. Wherefore he called that place Beer-sheba; because there they sware both of them."[115] The design of thus using the number being to give confirmation, such also must have been the end of using the oath. It is not improbable that the number seven may have been employed because that in seven days, according to the pattern set in the period of creation, and consequent sabbath, there are included the six days appointed for labour and the sabbath of rest. But, however that may be, we have the testimony of an inspired writer, that what was suggested in symbol by the number is the design of the oath. "An oath for confirmation is—an end of all strife."
Finally, a covenant with God, whether made in secret or in public, from its very nature cannot be entered into without an oath. Sometimes the vow and oath were used together. David "sware unto the Lord, and vowed unto the mighty God of Jacob." Mutual promises among men, though they confer obligation, do not always stand connected with a covenant with God, for they are made sometimes without a vow or an oath. But a promise made to God must be made either by vow or oath, or by both; and since no covenant with Him can be made without a promise, it follows that every covenant with Him is ratified by oath in its most explicit form, or by the oath implied in the vow.
FOOTNOTES:
[2] Hosea vi. 7.
[3] Jer. xxxiii. 20-25.
[4] Gen. viii. 22. See also Hosea ii. 18.
[5] Gen. xvii. 7.
[6] Zech. xiii. 9.
[7] Isa. lv. 3.
[8] Isa. xlv. 24.