The ruling on men growing their hair long

Question : The ruling on growing hair; growing hair means growing the hair on the head.

Answer : Is it a recommended practice (sunnah) or one of the permissible things? There is also disagreement among the scholars on this. The basis of the matter is that there is no doubt that the Messenger (peace and blessings be upon him) grew his hair, and that he did not shave his head except during Hajj or 'Umrah; this is an established fact. But did he grow it as an act of worship, or did he (may Allah have mercy on him) consider growing hair to be a recommended practice (sunnah)? He (may Allah have mercy on him) said that it is a recommended practice (sunnah) and that if we were strong enough, we would grow it. However, he has a word and a command, meaning it requires attention. A person who grows his hair must pay attention to it, meaning he must groom it. I said that Allah has made it obligatory for him to maintain it and to change the state of his head. From these three aspects—intending the time for its maintenance, leaving it, and Imam Ahmad’s view—if not, he considers it a recommended practice (sunnah). And those who consider it not an act of worship but a custom that the Prophet (peace and blessings be upon him) followed because the people in his time grew their hair, they say that it is not a recommended practice (sunnah). The closest and stronger position in our view is that it is a custom, not an act of worship. A person should follow the custom of his time and his country regarding growing his head hair. If the people grow it, he grows it and does not deviate from them. If the people do not grow it, he should not grow it, so that this falls under the category of customs, not acts of worship. This is exactly analogous to wearing the izar and the rida. Do you know that the majority of the Messenger’s (peace and blessings be upon him) clothing was what? The izar and the rida. Do we say now that it is recommended for a person to leave the suit and wear an izar and rida and a turban? If one of us were to wear an izar and rida and a turban now, they would say this is a sign of eccentricity and they would mock him. Yes, but in reality, this is a matter of custom, not a matter of the izar, nor a matter of growing hair. So growing hair is a custom: if the people grow it, do not deviate from them; if they do not grow it, do not deviate from them by growing it. As for what the modernists argued for by growing their hair, saying, "We follow the Messenger (peace and blessings be upon him)," this is in reality a matter of mocking the signs of Allah. This is mockery of the signs of Allah, which is forbidden, because the state of those who grow their hair like the hair of the rear and claim to be followers of the Messenger (peace and blessings be upon him) testifies against them that they are mocking it and departing from his way. They wrap the hair of the head for which no single text has ordered its growth, and they shave the beard which the Shari'ah has ordered to be grown. Then, if you consider their state, you will find that they do not pray, and if you look at the greatest of the legal matters, they are in opposition to them. So do we accept their claim and the intercession of the Messenger (peace and blessings be upon him) in growing the hair of the modernists?
Yes. The answer is that we do not accept that from them. As for the others who come to their shores, they are on their custom. He says: If you, O tribe, consider that to be the norm, there is no harm. But I am referring to those modernists who raised their heads against us and said, "We follow the Messenger, so why do you deny it to us?" We say: We deny it to you because you did not start with the Messenger in this, but rather you started with the customs and morals that came to you from the disbelievers.
As for the Messenger, you are not on the same path as them, except in the land of Islam if they are Muslims. And if they do not pray, it is well known that the one who does not pray is a disbeliever.