AsalamuAlaikum,
"Whoever imitates a group, then he is from amongst them" has been derived from two famous books of ahadeeth 'Mishkaat' and 'Abu Dawood' and is narrated by Hadhrat Ibn Umar (R.A). Whoever imitates a group (be they disbelievers or transgressors or even pious people), in acts of good or bad they will be regarded from amongst according to the sin or reward. By imitation here it is meant imitation in general, for example manners, clothing, figure and appearance, lifestyle etc. are included. That is why for those people who follow the trends of today and for example wear skin tight clothing, items of clothing which are unnecessarily torn in areas as part of its design, men who wear gold and silk, shave their beards or do not keep it according to the Sunnah and make fancy designs out of it, this hadeeth warns them of the severe punishment they are to expect if the they were to be raised with the disbelievers due to their acts of resemblance. Taking a look at the teachings and acts of the Holy Prophet Peace and Blessings be upon Him and of the Companions shows that even in matters that were optional and matters that were given preference to by Islam, the Holy Prophet Peace and Blessings be upon Him told us to refrain resembling them. Take for example the 10th date of the Islamic month of Muharram when it is preferable to keep fast. Due to the Jews also keeping fast on that same date, the Holy Prophet Peace and Blessings be upon Him ordered the Muslims to keep an extra day of fast, either on the 9th and 10th or the 10th and 11th if they had decided to keep fast on that day so as to not imitate the Jews. This just goes to show that even on small matters resemblance of the non-muslims is unacceptable. This message can also be seen in another hadeeth of the Holy Prophet Peace and Blessings be upon Him in which he orders us to oppose the polytheist by lengthening our beards and clipping our moustaches. This again is so that imitation of the wrong is not involved.
Haircuts
The imitation of different haircuts that we see being worn by our muslim youth is an indication towards how less interest they have in the way the shareeah has prescribed us to cut our hair. According to shareeah , hair should either be kept long and worn back i.e. until the hair from the tip of the forehead reaches midway to the earlobes, which is the minimum length, or up to the shoulders which is the maximum length. This sunnah style of hair is referred to as a 'zulfaa'. Male muslims can keep hair like this or they should cut the hair an even length all over. "
http://www.inter-islam.org/Prohibitions/Imitating.html#intro
"Whoever imitates a group, then he is from amongst them" has been derived from two famous books of ahadeeth 'Mishkaat' and 'Abu Dawood' and is narrated by Hadhrat Ibn Umar (R.A). Whoever imitates a group (be they disbelievers or transgressors or even pious people), in acts of good or bad they will be regarded from amongst according to the sin or reward. By imitation here it is meant imitation in general, for example manners, clothing, figure and appearance, lifestyle etc. are included. That is why for those people who follow the trends of today and for example wear skin tight clothing, items of clothing which are unnecessarily torn in areas as part of its design, men who wear gold and silk, shave their beards or do not keep it according to the Sunnah and make fancy designs out of it, this hadeeth warns them of the severe punishment they are to expect if the they were to be raised with the disbelievers due to their acts of resemblance. Taking a look at the teachings and acts of the Holy Prophet Peace and Blessings be upon Him and of the Companions shows that even in matters that were optional and matters that were given preference to by Islam, the Holy Prophet Peace and Blessings be upon Him told us to refrain resembling them. Take for example the 10th date of the Islamic month of Muharram when it is preferable to keep fast. Due to the Jews also keeping fast on that same date, the Holy Prophet Peace and Blessings be upon Him ordered the Muslims to keep an extra day of fast, either on the 9th and 10th or the 10th and 11th if they had decided to keep fast on that day so as to not imitate the Jews. This just goes to show that even on small matters resemblance of the non-muslims is unacceptable. This message can also be seen in another hadeeth of the Holy Prophet Peace and Blessings be upon Him in which he orders us to oppose the polytheist by lengthening our beards and clipping our moustaches. This again is so that imitation of the wrong is not involved.
Haircuts
The imitation of different haircuts that we see being worn by our muslim youth is an indication towards how less interest they have in the way the shareeah has prescribed us to cut our hair. According to shareeah , hair should either be kept long and worn back i.e. until the hair from the tip of the forehead reaches midway to the earlobes, which is the minimum length, or up to the shoulders which is the maximum length. This sunnah style of hair is referred to as a 'zulfaa'. Male muslims can keep hair like this or they should cut the hair an even length all over. "
http://www.inter-islam.org/Prohibitions/Imitating.html#intro
