Endnote 14 from Gender Equity in Islam 

In the event of a family dispute, the Qur'an exhorts the husband to
treat his wife kindly and not overlook her POSITIVE ASPECTS  (see
Qur'an 4:19).  If the problem relates to the wife's behavior, her
husband may exhort her and appeal for reason.   In most cases, this
measure is likely to be sufficient.  In cases where the problem
continues, the husband may express his displeasure in another peaceful
manner, by sleeping in a separate bed from hers.  There are cases,
however, in which a wife persists in deliberate mistreatment and
expresses contempt of her husband and disregard for her marital
obligations.  Instead of divorce, the husband may resort to another
measure that may save the marriage, at least in some cases.  Such a
measure is more accurately described as a gentle tap on the body, but
NEVER ON THE FACE, making it more of a symbolic measure then a
punitive one.  Following is the related Qur'anic text:

Men are the protectors and maintainers of women. because Allah has
given the one more (strength) than the other, and because they support
them from their means.  Therefore the righteous women are devoutly
obedient, and guard in (the husband's) absence what Allah would have
them guard.  As to those women on whose part you fear disloyalty and
ill-conduct, admonish them (first), (next) do not share their beds,
(and last) beat (tap) them (lightly); but if they return to obedience,
seek not against them means (of annoyance): for Allah is Most High,
Great (above you all). (4:34)
	
Even here, that maximum measure is limited by the following:

a.  It must be seen as A RARE EXCEPTION TO THE REPEATED EXHORTATION OF
MUTUAL RESPECT, KINDNESS AND GOOD TREATMENT,  discussed earlier. 
Based on the Qur'an and hadith this measure may be used in the cases
of lewdness on the part of the wife or extreme refraction and
rejection of the husband's reasonable requests on a consistent basis
(nushuz).  Even then, other measures, such as exhortation, should be
tried first.

b.  As defined by hadith, it is NOT PERMISSIBLE TO STRIKE ANYONE'S
FACE, CAUSE ANY BODILY HARM OR EVEN BE HARSH.  What the hadith
qualified as dharban ghayra mubarrih, or light striking, was
interpreted by early jurists as a (symbolic) use of miswak (a small
natural toothbrush)! They further qualified permissible "striking" as
that which leaves no mark on the body.  It is interesting that this
latter fourteen-centuries-old qualifier is the criterion used in
contemporary American law to separate a light and harmless tap or
strike from "abuse" in the legal sense.  This makes it clear that even
this extreme, last resort, and "lesser of the two evils" measure that
may save a marriage does not meet the definitions of "physical abuse,"
"family violence, " or "wife battering" in the 20th century law in
liberal democracies, where such extremes are so commonplace that they
are seen as national concerns.

c.  The permissibility of such symbolic expression of the seriousness
of continued refraction DOES NOT IMPLY ITS DESIRABILITY.   In several
ahadith, Prophet Muhammad (P) discouraged this measure.  Among his
sayings are the following: "Do not beat the female servants of Allah;"
"Some (women) visited my family complaining about their husbands
(beating them).  These (husbands) are not the best of you;" and"[It is
not a shame that] one of you beats his wife like [an unscrupulous
person] beats a slave and maybe he sleeps with her at the end of the
day." (See Riyadh Al-Saliheen, op.cit,p.p. 137-140).  In another
hadith the Prophet(P) said

...How does anyone of you beat his wife as he beats the stallion camel
and then he may embrace (sleep with) her?... (Sahih
Al-Bukhari,op.cit., vol.8.hadith 68,pp.42-43).
	
d.  True following of the sunnah is to follow the example of the
Prophet Muhammad (P), who NEVER RESORTED TO THAT MEASURE, regardless
of the circumstances.

e.  Islamic teachings are universal in nature.  They respond to the
needs and circumstances of diverse times, cultures and circumstances. 
Some measures may work in some cases and cultures or with certain
persons but may not be effective in others.  by definition, a
"permissible" act is neither required, encouraged or forbidden.  In
fact it may be BETTER TO SPELL OUT THE EXTENT  of permissibility, such
as in the issue at hand, rather than leaving it unrestricted and
unqualified, or ignoring it all together.  In the absence of strict
qualifiers, persons may interpret the matter in their own way, which
can lead to excesses and real abuse.

f.  Any excess, cruelty, family violence, or abuse committed by any
"Muslim" can never be traced, honestly, to any revelatory text (Qur'an
or hadith).  Such EXCESSES AND VIOLATIONS ARE TO BE BLAMED ON THE
PERSON(S) HIMSELF, as it shows that they are paying lip service to
Islamic teachings and injunctions and failing to follow the true
Sunnah of the Prophet (P).