Praise be to Allaah.

Letting the hair grow long is not a Sunnah for which the Muslim will be rewarded, rather it is the matter of custom and tradition. The Prophet (peace and blessings of Allaah be upon him) both let his hair grow long and shaved it, and he did not say that there was any reward for growing the hair long, nor is there any sin in shaving it, but he commanded men to take care of their hair. 

It was narrated from Abu Hurayrah (may Allaah be pleased with him) that the Messenger of Allaah (peace and blessings of Allaah be upon him) said: “Whoever has hair, let him take care of it.” Narrated by Abu Dawood, 4163; classed as hasan by al-Haafiz ibn Hajar in Fath al-Baari, 10/368. 

It was narrated that ‘Aa’ishah (may Allaah be pleased with her) said: I used to comb the hair of the Messenger of Allaah (peace and blessings of Allaah be upon him) when I was menstruating. Narrated by al-Bukhaari, 291. 

The hair of the Prophet (peace and blessings of Allaah be upon him) came down to his earlobes, or between his ears and his shoulders, or it reached his shoulders. When his hair grew long, he would put it in four braids. 

It was narrated from Anas (may Allaah be pleased with him) that the hair of the Prophet (peace and blessings of Allaah be upon him) reached his shoulders. Narrated by al-Bukhaari, 5563; Muslim, 2338. 

Anas ibn Maalik (may Allaah be pleased with him) said: The hair of the Messenger of Allaah (peace and blessings of Allaah be upon him) came down between his ears and his shoulders. Narrated by al-Bukhaari, 5565; Muslim, 2338. 

According to a report narrated by Muslim: The hair of the Messenger of Allaah (peace and blessings of Allaah be upon him) came halfway down his ears. 

It was narrated that ‘Aa’ishah (may Allaah be pleased with her) said: The hair of the Messenger of Allaah (peace and blessings of Allaah be upon him) came down longer than his earlobes and shorter than his shoulders. Narrated by al-Tirmidhi, 1755; Abu Dawood, 4187; classed as saheeh by al-Albaani in Saheeh al-Tirmidhi. 

It was narrated that Umm Haani’ (may Allaah be pleased with her) said: The Messenger of Allaah (peace and blessings of Allaah be upon him) came to Makkah and he had four braids. Narrated by al-Tirmidhi, 1781; Abu Dawood, 4191; Ibn Maajah, 3631; classed as hasan by Ibn Hajar in Fath al-Baari; classed as saheeh by al-Albaani in Mukhtasar al-Shamaa’il, 23. 

Al-Haafiz ibn Hajar (may Allaah have mercy on him) said: 

What is indicated by the hadeeth is that his hair usually came down to his shoulders, and sometimes it was so long that he wore it in braids, as was narrated by Abu Dawood and al-Tirmidhi with a hasan isnaad from Umm Haani’ who said: The Messenger of Allaah (peace and blessings of Allaah be upon him) came to Makkah and he had four braids. This is to be understood as referring to times when he was so preoccupied that he could not take care of his hair for a long time, such as when travelling and the like.  

End quote from Fath al-Baari, 10/360. 

This is something that was acceptable and usual according to the customs of that time. Customs vary and Muslims may be living in a place where people do not do that, or they regard the one who does that as imitating immoral people, so it should not be done. 

Shaykh Muhammad ibn Saalih al-‘Uthaymeen (may Allaah have mercy on him) said: 

There is nothing wrong with letting the hair grow long. The Prophet (peace and blessings of Allaah be upon him) had hair that sometimes came down almost to his shoulders. Although in principle there is nothing wrong with it, nevertheless it is subject to tradition and custom. If custom dictates that this is not done except by a specific group that is traditionally known to be immoral, then those who are decent and of good character should not let their hair grow long, because it is customarily regarded by the people as something that is only done by those who are of low status and immoral. So the issue of whether men may grow their hair long is something that is permitted, but is subject to the customs and traditions of the people. If custom dictates that all people, noble and lowly alike, grow their hair long, there is nothing wrong with it; if it is done only by the lowest of people, then people of honour and status should not do it. No one should respond by saying that the Prophet (peace and blessings of Allaah be upon him) – who was the noblest of people and the highest in status – used to grow his hair long, because we can see that growing one's hair long is not a Sunnah or an act of worship, rather it is the matter of following customs and traditions. 

Fataawa Noor ‘ala Darb 

What your husband says about the Prophet (peace and blessings of Allaah be upon him) having four braids is correct, but that does not mean that this is a Sunnah for which a person will be rewarded, rather the customs of the people and what they are used to should be heeded. Customs are different now in most countries from what they were in the past. 

Ibn ‘Abd al-Barr (may Allaah have mercy on him) said: 

Nowadays no one braids their hair except soldiers who have long hair; people of righteousness, modesty and knowledge have turned away from this custom, until that has become one of their distinguishing features. Nowadays long hair has virtually become the characteristic of the foolish. It was narrated that the Prophet (peace and blessings of Allaah be upon him) said: “Whoever imitates a people is one of them – or will be gathered with them (on the Day of Resurrection).” It was said that it means whoever imitates them in their actions, or whoever imitates them in their appearance. This should be sufficient for you. This hadeeth refers to following the example of the righteous in whatever they do. Growing one's hair or shaving it will not avail anything on the Day of Resurrection, rather what counts will be intentions and deeds; a man whose head is shaved may be better than one who has hair, or a man who has hair may be a righteous man. 

Al-Tamheed, 6/80 

Conclusion: we should follow custom and tradition with regard to that, so that the Muslim will not expose himself to people’s mockery and backbiting. 

And Allaah knows best.