Silk.
As for your question, it should be clear that there is nothing wrong with neckties unless they are made of pure silk. Responding to your question, Sheikh Ahmad Kutty, a senior lecturer and an Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states: "There is almost a scholarly consensus that wearing clothes made of pure silk in the form of a shirt or tie, etc., is forbidden for men. Some scholars permit it in exceptional cases such as when the man has a skin disease that requires wearing silk, or some kind of dire necessity, or because nothing else can be found to wear, etc. The above scholarly opinion concerning the prohibition of silk is based on the explicit statement of the Prophet (peace and blessings be upon him), "Wearing silk has been forbidden for the men of my Ummah." The Prophet's words are categorical in their implication, so there is no way to justify wearing pure silk in ordinary circumstances. Concerning clothes that are not made of pure silk, but are a mixture of silk and other substances such as cotton, acrylic, wool, etc., scholars are divided on the ruling about them. When one looks closely at the various views concerning this issue, it can be concluded that if silk is not the main substance of the cloth, then it is permissible; say for example: if a certain piece of cloth is 60% cotton and 40% silk, then it shall be considered permissible for men to wear." Allah Almighty knows best.When looking for the word "silk" in the Koran to find Mohammed's prohibition, though, I only see descriptions of Paradise, where silk (and gold jewelry, also haram for men) is in plentiful supply:
The CaveSo what is the reason for the prohibition? Islam Online gives us the inside info (after a discussion about how the reasons are irrelevant because one must follow Allah's will anyway):
1. [18.31] These it is for whom are gardens of perpetuity beneath which rivers flow, ornaments shall be given to them therein of bracelets of gold, and they shall wear green robes of fine silk and thick silk brocade interwoven with gold, reclining therein on raised couches; excellent the recompense and goodly the resting place.
The Pilgrimage
1. [22.23] Surely Allah will make those who believe and do good deeds enter gardens beneath which rivers flow; they shall be adorned therein with bracelets of gold and (with) pearls, and their garments therein shall be of silk.
The Originator
1. [35.33] Gardens of perpetuity, they shall enter therein; they shad be made to wear therein bracelets of gold and pearls, and their dress therein shall be silk.
The Smoke
1. [44.53] They shall wear of fine and thick silk, (sitting) face to face;
The Beneficent
1. [55.54] Reclining on beds, the inner coverings of which are of silk brocade; and the fruits of the two gardens shall be within reach.
Time
1. [76.12] And reward them, because they were patient, with garden and silk,
2. [76.21] Upon them shall be garments of fine green silk and thick silk interwoven with gold, and they shall be adorned with bracelets of silver, and their Lord shall make them drink a pure drink.
As for the point in question, the scholars have discussed the reasons for silk being forbidden for men. For example, ibn Al-Qayyim suggested in his brilliant work, Provision of the Hereafter, that:I could not find anyone to answer the next obvious question: if a man wants to disguise himself as a woman to perform a terror attack, is the prohibition against silk still in force?
“Among those who believe that there is reason and wisdom (behind the rulings of Islam) – and they are the majority – are some who answer that Islam has forbidden silk so that people will keep away from it for the sake of Allah, so they will be rewarded for that. Others reply that it’s basically created for women, as is the case with gold jewelry, so it’s forbidden for men lest it corrupts them by making them resemble women. Some scholars maintain that silk is forbidden because of what it may lead to in the way of pride and showing-off. Others relate the ruling (prohibition) to its having effect of femininity on men, as it goes against his masculinity and manliness. This applies to all men, even the most masculine and chivalrous of them. Whoever is too dense to understand this should just submit to the Wise Law-maker.” (Provision of the Hereafter, 4/80)"
And when will we be seeing the firebombing of stores that sell silk ties?