For people engage in Buddhist practice,a "vow" sets a goal in their practice so that they will work diligently towards achieving it. In Buddhism,one believes that you will have the strength to achieve something if there is a vow.When there is a vow,there is great strength.Vow can even surpass one's karma.Hence when there is a pious vow,miracles can happen.One has to learn and abide by it ,once one make it.One should make a vow and abide by it and strive towards it wholeheartedly.A vow that is not followed by action is an empty vow.Although there is a goal,it is not objective.It is something you do that expects nothing in return.