The “Vow” is prayerful and useful religious expression. It is an ancient habit that arrived, a human need to communicate with the divine. This acting has the same meaning when someone offers a gift to that person, who served him, appreciates and wants to offer him as a gratitude, for the present and the future.
Usually the religious vows are offers or counter-offers. All that usually "promise" and dedicate people called " vows/ tamata" meaning| of confide, trust, devote. It’s the exhortation and the reliance of gratitude for the strength that helps.