We all make promises. Some to God, some to people, some to ourselves. But we seldom ever keep them, do we? However, there are times it is wise not to keep a promise though we foolishly do in order not to appear like dogs who have gone back to their own vomit. Well, even though it sounds disgusting, no dog ever died of eating its own vomit and I would rather return to my vomit than eat a plate of dainty meats laced with poison.
People face problems when they make a promise out of zeal, cannot (or should not) honour it, and begin to wonder what people will say and so on and then go ahead to honour such promises in order to save face or appear to be people of their word. This is dignity without reason, whereby the desire to appear dignified overrules all tenets of common sense and propriety.
In his zeal, Jephthah (see Judges 11) promised God that "If You will give me victory over the Ammonites, I will burn as an offering the first person that comes out of my house to greet me, when I come back from the victory. I will offer that person to you as a sacrifice" (Judges 11:30-31). Little did he know that his daughter, his only child, would be the first person to dance out of his house rejoicing over his victory. Perhaps he had imagined it would be one of his slaves who would be offered as sacrifice. For dignity's sake, he eventually did what he had promised to the Lord.
I am not trying to contest fulfilling promises made to God. In fact, we should do our best to fulfil our promises to God. The point in this case is being careful and not allowing the zeal of the moment push us into making superfluous promises that we may find ourselves gnashing our teeth over. I also believe that God is merciful and if Jephthah had begged to be relieved of his vow, the Lord would have shown mercy because we know that the blessings of God make us rich without adding sorrow. The victory would have been surely given to Jephthah without the sorrow of losing his only child.
Another classic case of dignity without reason is the story of King Herod's birthday party where he promised his step daughter anything she asked for in exchange for the pleasure of watching her dance for him and his guests (Matthew 14:6-12). He was not expecting "anything" to include the head of John the baptist on a plate I guess. He kept his promise in order to save face and that was how John the baptist lost his life, because Herod chose to follow dignity without reason. Herod could have said no to her request, or scolded her for such a sanguine wish, but he chose to save face.
While there is dignity in keeping a promise, there is also dignity in admitting that a promise cannot be followed through for valid reasons. The world is full of people who are afraid of what other people will say. You do not have to be one of them.