It has been narrated in juridical, theosophical and ethical books that: prayer is reality that contains four thousand questions. This huge amount of external and internal questions represents the excellent position of prayer among the other worships. I don’t know how to start the declaration of this important spiritual action; I’m like a person who has stood near a beach and is looking at an extremely massive sea.
Two conditions have been stated for prayer: external, internal
In this section, the external and internal conditions of prayer will be mentioned simply and briefly.
External conditions
Purity includes the ablution, Vozu, Tayammom and removing contamination from body and attires and the cleanliness of prayer’s place the most that can be done.
Avoid to wearing silky and damask (hareer) attires and using golden material for men and the attires which have made from the wool of animals that have taboo meat.
Considering the time of prayer, it’s much better to say in the first time, and standing in a place where nothing and no one passes in front of prayer.
Standing toward the Kiblah with whole attention and concentration to this fact that what the prayer wants to do and he has stood in the presence of a great omnipotence.
Before saying the prayer, reciting some verses of holy Quran like:
إِنِّي وَجَّهْتُ وَجْهِيَ لِلَّذِي فَطَرَ السَّمَاوَاتِ وَالْأَرْضَ حَنِيفًا ۖ وَمَا أَنَا مِنَ الْمُشْرِكِينَ[1]
“Indeed, I have turned my face toward He who created the heavens and the earth, inclining toward truth, and I am not of those who associate others with Allah.”
Raising two hands to the near of ears while two palms are toward the Kiblah.
Standing courteously and dignifiedly in the presence of God and fixing eyes at the place of genuflection, especially to a clayish segment on which the prayer puts his forehead.
Takbeer and Sura Hamd and Toheed should be said with calmness, because hastiness and hurry in prayer removes its all divine effects.
Bowing and putting forehead on clay in Sajdeh along with placing two palm, two knees, two fingers of foot, saying Tashahhod and Salam by paying attention that morning prayer is two Rakats, noon prayer is four Rakat, afternoon prayer is four Rakats, evening prayer is three Rakats and night prayer is four Rakats.
This matter should be considered that in every Rakat of prayer after reciting Sura Hamd and Toheed and bowing one time and genuflecting for two times, and in the final two Rakats of the prayer which are four Rakats reciting Sura Hamd for one time or reciting “سبحان الله والحمد الله ولا اله الا الله و الله اکبر” one time according to the indult of religious expert whom prayer imitates from him.
These are external conditions of prayer that have been named the introductions of prayer.
source : Aspacts of prayer/ written by Prof. Hussain Ansarian