A vow may be binding even if its wording is incomplete or ambiguous; see
206:1-4;207:1;208:1-2;216:7. In doubtful cases release is required, and it
is also required if a vow is made using the wording of an oath or vice versa;
see 206:5 and 239:11. On the applicability of a vow after the thing that was
made forbidden has changed its state or its ownership see 216:1-12 and 223:3-4.
The terms used in an oath or vow are interpreted in accordance with common
usage; for examples see 215:6;217:1-48;239:1. The scope of the class of
things (or persons) included in an oath or vow is defined in accordance with
the swearer's intentions if they can be deduced; for examples see 218:1-6;
An oath or vow may be made conditionally (see 213:3;220:15;232:19;239:1),
but the condition must not conflict with the Halacha (see 222:1). A person
who breaks an oath or vow should keep it for at least an equal period of
time (but at most for 30 days) before being released from it, but if keeping
it would be a hardship, release can be granted immediately; see 208:2-5.
An oath or vow is binding only if it is made verbally and intentionally
(see 210:1;239:1); but a custom has the force of an oath or vow and requires
release (214:1). An oath or vow made in a dream requires release; see 210:2.
A person who makes an oath or vow may retract it provided he does so
immediately and verbally (210:3). On advance stipulations that oaths or
vows will not take effect see 211:1-4.
Vows can apply even to things that do not yet exist (204:4), but not to
insubstantial things such as speech (though such vows require release)
unless they involve observance of a commandment (213:1-2). Oaths can apply
even to insubstantial things (239:3). Vows that interfere with the
observance of a positive commandment or the fulfillment of an oath are
usually valid (see 215:1-5;227:3). On vows that involve things that are
already forbidden either by a commandment or because of an oath see
215:5-6;228:15;238:18-19. On contradictory or redundant oaths or vows
A person is punished for swearing to violate a commandment and such an
oath must not be kept (see 236:5;238:5;239:4-8). If a person swears to
perform a positive commandment the oath is ineffective (see 238:4), but
if he swears not to violate a negative commandment and does violate it
he is punished also for violation of the oath. If a person swears to
perform actions which include violations of negative commandments he must
not violate them, but if he swears not to perform actions which include
positive commandments he need not perform them (see 236:5;238:6;239:4).
Shulchan Aruch, Copyright (c) 2000 ProjectGenesis, Inc.