If a man vows a vow to God, or swears an oath to bind his soul with a bond; he shall not break his word, he shall do according to all that proceeds out of his mouth. (Bamidbar 30:3)
Speech is a defining human quality. The ability to articulate our thoughts into specific words is what sets us apart from the animals. Man is thus obligated by their words in a type of a social contract, a necessary institution for a cohesive society. In fact, the theme of the gravity and sanctity of human speech carries through the whole Torah — from the first “Hineni” – “here I am”, expressing Abraham’s willingness to follow God’s instructions to the words Moses is directing to the Israelites in the wilderness.
In our Torah portion, we are introduced to the topic of vows. A vow links words and action in a new way: It binds today’s speech with tomorrow’s action. This is explained concisely by R. Zvi Elimelech Shapira (1783-1841): A person does not feel tomorrow’s evil inclination today. Often, a person knows what they should do, or what they would like to do, and a vow helps them to overcome the human gap between thought and action. When one is unable to reach their intended goal today, they bind themselves to their ability in the future, which is as yet untainted by weakness or temptation. An everyday example is the person who knows he should start a diet; today, he is confounded by today’s yetzer hara, and declares, „Tomorrow I will begin.“ The vow helps defeat the yetzer hara of tomorrow before it rears its seductive head. By using words, which are themselves a Divine tool, man can bring God into the situation, make God an ally; hopefully, that will spiritually fortify the person and provide the strength needed to succeed.
In other words: Thought and action should be unified. The purpose of a vow is to unite the inner thought, as expressed by words, with actions. When our thoughts become disconnected from our words, or words from actions, we are being dishonest. This dishonesty may or may not affect others in a particular instance, but it always impacts upon ourselves, upon our inner world. When we create consonance between our thoughts, words and actions, when we purposefully and steadfastly work to bring them closer together, we become more like God, whose words, thoughts and actions are one.
– Rabbi Adrian M Schell
(Source: Rabbi Ari Kahn)