In the Scripture we are told that no doctrine is of any private interpretation, which means that all valid doctrines are established by several different passages and verses that are all contextually addressing the same issue in the same way.
Perhaps if we examine what the Scripture does state about guaranteeing future behavior, and guaranteeing our words, we might have a better understanding of what our real condition is. Moreover, we might get a little more humble about how wonderful we think we are as individuals. We also might gain a better understanding of why it is the LORD made certain it was declared in His word.
In understanding why this is, we should note that a vow is the same a swearing that one will fulfill a promise, either in word or deed. Which means that people are going to look at you funny if you refuse to swear in court, or upon entrance in government service. (By the way, just how many government officials have broken their oaths of office?) Whether people consider one odd or not, is not the issue here. What is the issue is why we should, or should not swear, and what God does in response to someone swearing an oath – whether they are His child or not. However, to confirm or deny this doctrine, we need to go further, which brings us to the Gospel of Matthew and the words of the Lord Jesus Christ:
Again, ye have heard that it hath been said by them of old time, Thou shalt not forswear thyself, but shalt perform unto the Lord thine oaths: But I say unto you, Swear not at all; neither by heaven; for it is God's throne: Nor by the earth; for it is his footstool: neither by Jerusalem; for it is the city of the great King. Neither shalt thou swear by thy head, because thou canst not make one hair white or black. But let your communication be, Yea, yea; Nay, nay: for whatsoever is more than these cometh of evil. (Matthew 5:33-37)
Plainly, the Lord stated here that one should not swear at all – period. He gives a couple of examples of things we have no power to control, and tells us that if we have no power to control these things, we certainly ought not swear concerning future words and deeds. This is briefly confirmed in James, chapter five:
But above all things, my brethren, swear not, neither by heaven, neither by the earth, neither by any other oath: but let your yea be yea; and your nay, nay; lest ye fall into condemnation. (James 5:12)