When performing Salah there are requirements called (shuroot) or conditions which need to be met before starting Salah. If the fulfillment of any one of these conditions is missed then the Salah is invalid.

1. Islam: Acts of worship are not accepted without the person being a Muslim. Allah said: {Yet truly it has been revealed to you, [O prophet]- and to those [of prophets] before you: If ever you were to associate [any] gods with God, then utterly futile would be all your [good] works. And, most surely, you yourself would have become among the losers [of everlasting Paradise]} 39:65.
2. Sanity: The prophet (PBUH) said: “The Pen [documenting deeds] is lifted of three people: A person sleeping until he wakes up; an insane (or mentally disabled) person until he regains sanity; and a child until he reaches puberty.”
3. Tamyeez: It is the age when the child is able to differentiate between things based on his understanding. This condition is concluded from the Hadith of the prophet (PBUH): “Order your children to pray at the age of seven.”
4. Cleanliness of Body: It includes cleaning the private area after using the washroom. If any part of the body was touched by filth too it has to be cleaned before performing prayer. Allah said: {Indeed, God loves those who are ever-penitent, and He loves those who purify themselves} 2:222.
5. State of purity: This means that Wudu or ablution must be performed, and if intimately impure then a bath must be taken. Allah said: {O you who believe! When you rise for the prayer, wash your faces, and your hands to the elbows, and [wash] your feet to the ankles. And when you become ritually unclean, then cleanse yourselves [thus]} 5:6
6. Cleanliness of clothes: The garments that people wear must also be in a state of cleanliness. Allah said: {And your garment thus purify} 74:4.
7. Cleanliness of place of prayer: The story of the bedouin who urinated in the Mosque and the prophet (SAAW) ordered his companions to wash the place touched by urine confirms this condition.
8. Covering Awrah: Awrah is the private parts of the body that cannot be exposed during Salah. Allah said: {O Children of Adam! Don your adorning apparel when setting out for every place of worship} 7:31.
   • Awrah for males includes between belly and knees. Some scholars like Imam Ibn Hazm say that the thigh is not included in Awrah for men. He supports that by two Hadiths – the first in which Anas saw the white thigh of the prophet during the Day of Khaibar (Hadith narrated by Bukhari) and the second when Abu Bakr, Omar and Othman entered by the prophet (PBUH) and his thigh was exposed and he did not change his position until Othman entered. (Hadith narrated by Ahmad.)
   • Awrah for females is different among scholars. The school of Hanabilah says all body except for face. The school of Shafeiah says all body except for face and hands. School of Hanafiah says all body but face, hands and feet.
9. Time of Salah is valid No one can pray before the time enters for each Salah. If someone missed the time it will be considered (Qada’) a makeup and it is a sin to delay Salah. Allah said: {Indeed, the prayer is [a] prescribed [obligation] for the believers at the [well know] appointed times} 4:103.
10. Facing QiblahQiblah means the direction toward the sacred Mosque (Al Kaabah) in the city of Makkah. Allah said: {[O Prophet!] We have, indeed, seen your face turn [in supplication] toward the heaven. Therefore, We shall turn you toward a direction of Prayer that is pleasing to you. So, [there forth,] turn your face [in prayer] toward the Sacred Mosque} 2:144.