How valid is our promise that we make to others and even to God?  Jesus warns us that we might be thinking to highly of ourselves when we take oaths.  There is nothing that man has that God does not already own.  There is nothing that anyone can offer to God that he would have to forfeit if he broke his oath, except perhaps his own soul.  And this is the very thing that man refuses to offer to God.  So the point that Jesus is teaching us here about oaths is that all we have is our word and we ought to be very careful when making an oath or even a promise especially to God since we really don’t have the power to keep it.  Circumstances can change of which we have no power to control.  For this reason James rephrases Jesus words in his epistle as follows:

James 4:14-16 (KJV)
¹⁴Whereas ye know not what shall be on the morrow. For what is your life? It is even a vapour, that appeareth for a little time, and then vanisheth away.
¹⁵For that ye ought to say, If the Lord will, we shall live, and do this, or that.
¹⁶But now ye rejoice in your boastings: all such rejoicing is evil.

Therefore we should not think too highly of ourselves to think that we are independent of God and that we possess anything including the hair on our heads that can make our word any more credible or reliable.

We have no right to use anything for collateral to support the truth of our word than our word itself.  So we should make it a practice to consider answering only “yes” or “no” and adding the phrase “If the Lord wills . . .”