Source: Common Mistakes done during Prayer by: Mashhur Hasan Salman
Wearing tight clothes is detested legally and medically for their harmful effect on the body. Sometimes the person cannot prostrate (properly) while wearing such clothes. If wearing them leads to leaving the prayers (or some acts of them), then wearing them is Haram (illegal).
It was proven through experiments that most of those who wear such clothes do not pray, except a little, like the hypocrites.
Most of the Praying Muslims nowadays unfortunately pray while wearing tight clothes that display the genitals: one of them or both.
Albani , (the great Hadith contemporary scholar) may Allah (Subhanaahu Wa Ta’alaa) have mercy on him, said: “Trousers shape the genitals.” The loin (part) of the man is from the knee to the navel. The praying person should avoid the disobedience of Allah (Subhanaahu Wa Ta’alaa) , the Exalted, (especially) when he prostrates to Him. When any person wears tight clothes, then you can see (the shape of) his genitals clearly, not only that but also between them. How could a person (in such state) offer his prayer and stand between the hands of [Allah (Subhanaahu Wa Ta’alaa) ] the Rabb of the worlds. But if the trousers are wide enough and not tight, offering the prayer in that case is correct and it is better if he (the praying person) wears (wide) shirts that cover the part between the knee and the navel.
- Resting only the tip of the nose on the floor during Sujood
- 'Ithikaf (Private Devotion in Masjid)
- Moving the Finger in Tashahhud.
- Abandoning the Friday prayer