Why is it haraam for the pilgrim to wear sewn garments?

Question

Praise be to Allah.

Firstly: Allaah has
enjoined Hajj once in a lifetime for those who are accountable and who are
able to do it and have the means, and He has made it one of the pillars of
Islam, as is well-known in Islam. So the Muslim has to do that which Allaah
has enjoined upon him, to please Allaah and obey His command, hoping for His
reward and fearing His punishment, whilst trusting that Allaah is Wise in
His laws and in all that He does, and that He is Merciful towards His
slaves, so that He would not prescribe for them anything but that which is
in their best interests and which will be of great benefit to them in this
world and in the Hereafter. It is for our Lord, the Sovereign, the All-Wise,
to issue laws, and it is for His slaves to obey and submit.

Secondly: there are many reasons why it is prescribed for us
to avoid sewn garments during Hajj and ‘Umrah. For example: to remind us of
how people will be on the Day of Resurrection, for they will be resurrected
barefoot and naked, then they will be clothed. Reminding ourselves of how
things will be on the Day of Resurrection teaches us an important lesson. It
also makes us humble and makes us feel that we are obliged to submit and
cleanse ourselves of arrogance. And it reminds us of the principles of
rapprochement, equality and asceticism, and of keeping away from the
luxurious life which is condemned, and it makes us feel empathy for the poor
and needy… and there are other aims behind doing Hajj in the manner
prescribed by Allaah and explained by His Messenger (peace and
blessings of Allaah be upon him).

And Allaah is the Source of strength. May Allaah send
blessings and peace upon our Prophet Muhammad and His family and
companions.

Standing Committee for Academic Research and Issuing Fatwas,
Fataawa al-Lajnah, 11/179

(* Note: What is meant by sewn garments is not those which
are stitched, rather it means those which are fitted to parts of the body,
such as jackets which are fitted to the arms and chest, or pants which are
fitted to the legs, or leather slippers (khuffayn) which are fitted to the
feet, or gloves which are fitted to the hands. On that basis it is permitted
to wear a watch which has stitching on the strap, or shoes on which there is
stitching, or a belt in which there is stitching, and so on).