1. Shaykh Al-Uthaymeen and others have mentioned that the condition of
   being in the state of Islam and having sanity and discernment are
   general conditions which are not confined to the prayer. Therefore,
   they should not be specified as being from the conditions of the
   prayer.
2. The Scholars have used wordings such as shuroot and arkaan and
   waajibaat for the prayer as a guideline to understand and comprehend
   the prayer, although such wordings are not found in the hadeeths.
3. Ash-Shawkaane has mentioned that some have mentioned that the
   recitation of al-Faatihah is a condition of the prayer. However, the
   correct opinion is that it is a pillar due to it being within the prayer.
4. Ash-Shaykh al-Uthaymeen mentioned that facing the Qiblah is a
   condition for the prayer by the consensus of the scholars except in four
   situations.
5. Having an unrestricted niyyah (i.e. intention) is not sufficient
   for the prayer; it is a condition that the one who wishes to pray has a
   restricted intention wherein he specifies in his heart which prayer he
   intends to pray.
6. The actions of the disbelievers are in vain and futile as the particles of dust.
7. Sanity is a condition from two angles, the first being he needs to be sane to comprehend the act of worship which he wishes to perform and the second angle being he needs to have a niyyah (an intention) for it
   [A benefit from Ash-Shaykh al-Uthaymeen]
8. If an insane person returns to his senses while the prayer time is still in, then it is compulsory upon him to pray.
9. Being unconscious or intoxicated goes underneath the ruling of insanity.
10. Ash-Shawkaanee mentioned that the one performing the prayer only
    receives from his prayer that which his mind is present for.
11. Upon the correct opinion, the conditions [for the validity of prayer] are four. In summary:
    1. Being upon purity
    2. Niyyah
    3. Facing the Qiblah
    4. The entering of the time for prayer

Mentioned by

AbdulFattaah bin Uthman
Abu Fajr