The Necessity of Oaths
"When the sun had gone down and it was dark, behold, a smoking fire pot and a flaming torch passed between these pieces. On that day the LORD made a covenant with Abram" (vv. 17–18).
As we continue our study of what the Bible has to say about swearing oaths and vows, it will be important for us to remember that the reason why oaths and vows are necessary has to do with our fallen condition. In a perfect creation, we would not need to call upon the Lord in the presence of many witnesses in order to have a tangible means of holding us accountable to our word. We would, by nature, always keep our word. We would need to offer nothing besides our word in order to give others confidence that we will keep it. And there would be no danger that we would fail to keep our word, so we would not need anyone outside ourselves to call us to account for breaking a promise.
We all know, however, that we do not live in a perfect world. Though God originally created everything "very good" (Gen. 1:31), creation no longer exists in that state. Creation is fallen, and that fall has affected everything, including the truthfulness of our words. We have all been betrayed by others who have broken their promises to us. Broken marriage vows, business contracts, political promises, and pledges to our children, friends, and parents have damaged human society. Sadly, it is true that "all mankind are liars" (Ps. 116:11) and that we are full of deceit (Rom. 1:29). This does not mean that everything everyone ever says is a lie; rather, it indicates that none of us has told the truth on every occasion and that we remain prone to bend the truth, to tell half-truths, and to lie.
Therefore, God in His grace instituted oath-swearing as a means to help curb the effects of the fall. Oaths and vows establish a system whereby there is an external restraint on lying and a way to hold those who love falsehood accountable. Yet as we read Scripture, we find that even God Himself has sworn oaths (Heb. 6:13–20). Does this then mean that even the Lord has a propensity to lie? May such a thought never cross our minds. God's oaths are, in fact, a condescension to our limitations as fallen creatures. In our weakness, we need assurances to keep trusting in our Creator. God gave such an assurance when He swore an oath to Abraham. In passing between the pieces of the dead and dismembered animals, the Lord told Abraham that the same fate would befall Him if He were to break His pledge to the patriarch (Gen. 15). Obviously, the Lord cannot be killed, so this oath is a tangible sign that our Creator is certain to keep His promises. It also indicates that oaths are appropriate when making a covenant, for that is the context of Genesis 15.
Coram Deo
Christians are to be so trustworthy that no one would need to demand an oath of us in ordinary circumstances in order to be sure that we will keep our word. In the context of making a solemn covenant, however, things are different. At such times, making a vow is quite appropriate. In fact, we should desire to make the oath so that we are reminded that others will hold us accountable if we should violate our word.