Is Praying In Pants Invalid?
Question

Is praying in pants invalid? I have heard some people say that because pants show the shape of the `Awrah.
Praise be to Allah.The Importance of Proper Attire for Prayer
Allah has commanded the one who wants to pray to wear his adornment. Allah says (interpretation of the meaning):
{O Children of Adam! Take your adornment (by wearing your clean clothes) while praying[and going round (the Tawaf of ) the Ka`bah] and eat and drink but waste not by extravagance, certainly He (Allah) likes not Al-Musrifun (those who waste by extravagance).} [Al-A`raf 7:31]
So the one who wants to pray is enjoined to adorn himself for prayer, and not to do what many Muslims do, unfortunately, which is praying in their nightclothes or work clothes, and not beautifying themselves for prayer, for Allah is beautiful and loves beauty.
The scholars regard the minimum level of adorning oneself to be covering the `Awrah . Hence they stated that covering the `Awrah is one of the necessary conditions of prayer being valid, and prayer is not valid unless the `Awrah is covered.
What is implied by their saying “covering the `Awrah” is that what is obligatory is covering the `Awrah, and that no matter what is used to cover the `Awrah, the prayer is valid, even if it is a tight garment that shows the shape of the `Awrah .
Scholarly Opinions on Praying in Tight Clothing
This is what has been stated clearly by the scholars of the various schools of Fiqh (Madhhabs). There follow their comments on that.

The Hanafi Madhhab:

It says in Al-Durr Al-Mukhtar (2/84): It does not matter if it clings to the body and shows the shape of the body. (End quote – i.e., the garment that one wears when praying)
Ibn `Abidin (may Allah have mercy on him) said in his commentary on Ad-Durr Al-Mukhtar: The phrase “It does not matter if it clings to the body”, such as if it clings to the buttocks, but if it is thick and the colour of the skin cannot be seen through it, but it clings to the limb and shows its shape so that the shape of the limb is visible, then that does not mean that the prayer is not permissible, because the `Awrah is still covered. End quote from Ibn `Abidin.

The Shafi`i Madhhab:

An-Nawawi (may Allah have mercy on him) said in Al-Majmu` (3/176): If the colour is concealed but the size of the limb can be seen, such as the knee or buttocks and so on, the prayer is valid because the `Awrah has been covered. Ad-Darimi and the author of Al-Bayan stated that it is not valid if the shape can be seen, but this is an obvious mistake. (End quote)

The Maliki Madhhab:

It says in Al-Fawakih Ad-Dawani, 1/216:
“It is valid if a man prays in a single garment”: that is subject to the recommended condition that it should be thick enough so that it does not show anything, otherwise it is disliked, and it should cover all of his body. If it covers only the `Awrah that is most private, or it shows the shape of the `Awrah, then it is disliked to pray in it, and the prayer should be repeated if there is enough time left. (End quote)
It is mentioned that it is disliked to pray in a garment that shows the shape of the `Awrah, not that it is prohibited.
It says in Hashiyat Ad-Dusuqi that praying in a garment that shows the shape of the `Awrah is valid , but it is slightly disliked, and it is recommended to repeat the prayer if there is enough time left.
It says in Balghat As-Salik (1/283):
It is essential that the material be thick i.e., it should not be see-through at a glance, and it should not be see-through at all, or it may be see-through when staring at it.  If it is see-through at a glance, then it is as if it was not there (i.e., it is as if he is praying naked, because he is not covered). But if it is see-through when staring at it then he should repeat the prayer if there is time, as when the clothing shows the shape of the `Awrah, because praying in such a garment is makrooh according to the correct view. (End quote)

The Hanbali Madhhab

Al-Bahuti (may Allah have mercy on him) said in Ar-Rawd Al-Murbi` (1/494):  It is not a condition that the garment should not show the shape of the body or part of the body, because this cannot be avoided.
Ibn Qasim (may Allah have mercy on him) said in his commentary on Ar-Rawd Al-Murbi`, commenting on the words of Al-Bahuti quoted above: that is in agreement with the three imams, Abu Hanifah, Malik and Ash-Shafi`i (may Allah have mercy on them); i.e., the view of Imam Ahmad concerning this matter is in accordance with the view of the three other Imams.
Ibn Qudamah (may Allah have mercy on him) said in Al-Mughni (2/287): If it conceals the colour but shows the shape, the prayer is permissible, because this cannot be avoided. (End quote)|
Al-Mardawi said in Al-Insaf (1/471):
Al-Majd ibn Taymiyah said: it is disliked for a woman to tie something over her clothes (such as a belt), lest that show the size of her limbs and body. Ibn Tamim and others said: it is disliked for a woman to pray with something tied around her waist such as a wrapper or belt, etc. (End quote)
Shaykh Sayyid Sabiq (may Allah have mercy on him) said in Fiqh As-Sunnah (1/97):
It is obligatory to wear garments that cover the `Awrah even if it is tight and shows the shape of the `Awrah. (End quote)
These are the comments of the scholars on praying in tight garments that show the shape of the `Awrah. They clearly state that the prayer is still valid.
Does Tight Clothing Affect the Validity of Prayer?
But that does not mean that people are encouraged to pray in tight clothes, rather they should not wear tight clothes or pray in them, because that is contrary to the adornment that we are enjoined to wear when praying. Rather the issue here is whether the prayer is valid or not.
Shaykh Salih Al-Fawzan has issued a fatwa stating that if a woman prays in tight clothes that show the shape of her `Awrah, her prayer is valid, although she is sinning by wearing these clothes.
He said:
It is not permissible to wear tight clothes which show the limbs and the shape of a woman’s body and buttocks . Tight clothes are not permissible for men or women, but it is especially forbidden for women, because the Fitnah in their case is greater.
With regard to praying in particular, if a person prays with his `Awrah covered in such clothes , his prayer is valid in and of itself, because the `Awrah is covered, but he is sinning by praying in tight clothes, because he has transgressed one of the prescribed requirements of prayer by wearing tight clothes . This is one aspect. Another aspect is that it is a cause of temptation and attracts attention, especially in the case of women. So women should cover themselves with loose garments which will cover them and not show any of the limbs of their body or attract attention. So it should not be a thin or see-through garment, rather it should be a concealing garment which will cover the woman completely. (End quote from Al-Muntaqa min Fatawa Ash-Shaykh Salih Al-Fawzan, 3/454)
Some scholars have explained the words of the Prophet (peace and blessings of Allah be upon him), “Women who are clothed yet naked” as referring to women who wear tight clothes.
And Allah knows best.