A vow that permits that which the Bible made forbidden, is not a valid vow. This verse is mysterious. This can come teach us an important lesson about dealing with people. There are many times when somebody will say 'I will do this or that', and then not do what was said. It is important for a person to keep his word, and not just talk big and without thought.
Talk is cheap, but keeping one's word shows personal integrity and fine character.
Please pass it on to a friend. SUB bytetorah .