There is a difference

There is a fundamental distinction between a vow and an oath. A vow is a conditional promise that seeks to bargain with a deity to support a desired outcome. Most notable vows articulate the arrangement in positive terms; expressing how each party will mutually benefit when the agreement is fulfilled. Vows generally lack any references to penalties for a failure to meet the vow’s demands. This may be attributed to the fact that a human being cannot punish a deity for not honoring the arrangement. The freedom of divine will must be respected. However should a mere mortal fail to thank the deity for his or her generosity by fulfilling the vow, we can presume that there would be repercussions. Yet again, this leaves the deity free to determine exactly what that punishment will be.

An oath, on the other hand, is a conditional curse. It solicits a deity or deities to punish someone for failure to respect and maintain the terms of an arrangement. One of the more interesting characters {sic] of ancient oaths is that they could be exacted in two different ways. One method allowed one to bind oneself to the agreement. This is an oath as a conditional self-curse. Thus, the one who swears the oath generally determines the nature of the punishment as expressed in the curse. The other method allows a superior party to impose an oath on another person. Here, the superior party unilaterally establishes all features of the oath from every detail of the terms, to expansive lists of curses.— Cursed Are You!, pages 61-62