A promise is a psychological contract indicating a transaction between two persons whereby the first person undertakes in the future to render some service or gift to the second person or devotes something valuable now and here to his use. A promise may also be any vow or guarantee.
Promises and religions
Religions have differing attitudes towards promises.
Christianity
In Christianity, a distinction is made between simple promises and oaths/vows, with only the latter being seen as involving God, either as witness to the promise or recipient of it, although He sees the simple promises too.The act of making a solemn oath may be done on one's own, but certain oaths or vows, especially when it effects a person's vocation in life and role in the community, are made publicly, and before a priest or public official. A Christian who makes an oath to God is responsible for it, not to the peril of his soul, but as a sin if he breaks it.Certain sects of Western Christianity, amongst them
Source:
http://en.wikipedia.org/wiki/Promise