We are aware of the number of
rakats that are there in each
salat. How did we get these numbers ? Are they mentioned in any hadith ? Also, the number of
rakats that are
farz and those that are
wajib.. where are all these mentioned ?
We got the number of Rakat of Salat from authentic Ahadeeth. The number of Rak'at for both Fard and Sunah Salat (I believe that is what you mean by Wajib) were perserved in the Authentic Ahadeeth as well as the Practice of those who followed the way of the Prophet (Peace and blessings be upon him) and the order
صلوا كما رأيتموني أصلي
Pray as you have seen me pray
The Ahadeeth which are narrated, are found in different books of Hadith and not only in one, the number of Rak'at for the fard Salat are:
صَلاَةُ الصُّبْحِ رَكْعَتَانِ
There are two rak'ahs of the dawn prayer (i.e. the prescribed rak'ahs).
Zuhr, Asr, Maghrib, and Isha'
حدثنا يعقوب قال حدثنا أبي عن ابن إسحاق قال حدثني صالح بن كيسان عن عروة بن الزبير عن عائشة زوج النبي صلى الله عليه وسلم قال قالت كان أول ما افترض على رسول الله صلى الله عليه وسلم الصلاة ركعتان ركعتان إلا المغرب فإنها كانت ثلاثا ثم أتم الله الظهر والعصر والعشاء الآخرة أربعا في الحضر وأقر الصلاة على فرضها الأول في السفر
Among that which was obligated on the Prophet (صلى الله عليه وسلم) was Salat which was two Rak'at two Rak'at except for Maghrib which was three, and then Allah made Zuhr Asr and Isha' four while one is not Traveling, and made it the same as it was obligated the first time while Traveling (meaning Two Rak'at)
مسند الإمام أحمد (Ahmed hadith 25806)
The messenger PBUH said "pray like you saw me pray".
This is the best way to preserve the way praying should be done.
If the description of praying was transcribed then it would have been easy to alter it and modify it by modifying it in some books.
All the details of praying was preserved from generation to generation through practical education. It is not always a good idea to write down everything.
the correct hadith is "pray like you saw me pray". meaning there shouldn't be a "narration" but rather a sunnah that a generation will teach the next, just like bukhari learned how to pray from his mom probably just like you and me - not from a book - the point of the question is to realize that we dont need the hadith to learn how to pray-
an nisa: 102: And when you are among them and lead them in prayer, let a group of them stand [in prayer] with you and let them carry their arms. And when they have prostrated, let them be [in position] behind you and have the other group come forward which has not [yet] prayed and let them pray with you, taking precaution and carrying their arms. Those who disbelieve wish that you would neglect your weapons and your baggage so they could come down upon you in one [single] attack. But there is no blame upon you, if you are troubled by rain or are ill, for putting down your arms, but take precaution. Indeed, Allah has prepared for the disbelievers a humiliating punishment.
From the above aya it is evident that every namaz have 2 fard rakat. Allah commands us to perform full namaz when you are not in fear. Aya showing that during the war they did the half salat means one rakat by one group and another group perform one rakat. This is the strongest evidence for rakat of namaz for every salat. Question arise that how can you perform maghrib salat half when you are in the state of fear. How is two rakat is jahri and two rakat is sari. If performing half salat 2 rakat it means you do one rakat jahri and one rakat sarri but we are not doing that, we just pray two rakat jahari and skip the sarri, which is not right. May Allah guid us and show us the right path. ameen