1. Understanding the Sunnah Prayers
The Duha Prayer

2. The Duha prayer is a voluntary prayer that when prayed brings many reward:
Abu Zharr reports that the Prophet said: "Charity is required from every part of your body daily. Every saying of 'Glory be to Allah' is charity. Every saying of 'Praise be to Allah' is charity. Every saying of 'There is no God but Allah' is charity. Every saying of 'Allah is the Greatest' is charity. Ordering the good is charity. Eradicating the evil is charity. And what suffices for that (as a charity) are the two rak'at of duha."
[ This is related by Ahmad, Muslim, and Abu Dawud.]
Ahmad and Abu Dawud record from Buraidah that the Prophet said: "In a human (body) there are 360 joints and man must make a charity for each one." The people said: "Who can do that, O Messenger of Allah?" He responded: "One may cover the mucus that one finds in the mosque or remove something harmful from the road. If one could not do that, he could pray two rak'at of duha and that will be sufficient for him."

3. Other hadith:
An-Nawas ibn Sam'an relates that the Prophet sallallahu alehi wasallam said: "Allah said: 'Son of Adam, do not fail in performing four rak'at in the early day as it will be sufficient for the latter part of the day."' This is related by al-Hakim and at- Tabarani and its narrators are trustworthy. Ahmad, at-Tirmizhi, Abu Dawud, and an-Nasa'i relate it on the authority of Na'im al-Ghatfani with a good chain. At-Tirmizhi's wording is: "Son of Adam, pray four rak'at for Me in the early day and it will be sufficient for you for the latter part of the day."
Abdullah ibn 'Amr says: "The Messenger of Allah sent an expedition and they obtained lots of booty and returned quickly. The people talked about their quick victory, abundant booty, and quick return. At this the Messenger of Allah said: 'Shall I not guide you to a closer battle, a greater booty and a quicker return? Whoever makes wudu' and then goes to the mosque to pray duha, that is the closer battle, better booty, and quicker return."'
[This is related by Ahmad and at-Tabarani. Abu Ya'la has something similar to it].
Abu Hurairah says: "My friend [the Messenger of Allah] advised me to do three things: fasting three days of every month, praying the duha prayer, and praying the witr prayer before I sleep."
[This is related by alBukhari and Muslim]
Anas says: "During a journey, I saw the Messenger of Allah pray eight rak'at in the early day. When he finished, he said: 'I prayed my prayer wishing and fearing. I asked my Lord for three things and He gave me two and withheld one. I asked Him not to put my ummah to trial by famine and He granted that request. And I asked that they would not be overtaken by their enemies and He granted that request. And I asked that they not be split into groups and parties and He refused that request."'
[this is related by Ahmad, an-Nasa'i, al-Hakim, and ibn Khuzaimah who classifies it as sahih].

4. The Time for the Duha Prayer
The time for duha begins when the sun is about a spear's length above the horizon and it continues until the sun reaches its meridian. It is preferred to delay it until the sun has risen high and the day has become hot.
Zaid ibn Arqam relates: "The Messenger of Allah went to the people of Quba', and they were performing duha, and he said: 'The prayer of devotion should be observed when the young weaned camels feel the heat of the sun.'"
[This is related by Ahmad, Muslim, and at- Tirmizhi .]

5. How many rakaats for the Duha Prayer
The minimum number of rak'ah to be prayed is two, as was mentioned in the hadith of Abu Zharr. The most that the Prophet performed was eight rak'at, whereas, the most he mentioned was twelve rak'at.
Sa'id ibn Mansur records that al-Hassan was asked: "Did the companions perform it?" He answered: "Yes some of them would pray two rak'at and some of them would pray four rak'at. And some of them would continue until half the [early] day [had passed]."
Ibrahim an-Nakha'i reports that al-Aswad ibn Yazid was asked: "How many rak'at are to be prayed for duha?" He answered: "As many as you wish ."
Umm Hani narrates that the Prophet prayed eight rak'at of duha and made the taslim after every two rak'at. This is related by Abu Dawud with a sahih chain.
'Aishah reports: "The Prophet would pray four rak'at for duha and would add to it whatever Allah willed." This is related by Ahmad, Muslim, and ibn Majah.

6. To Be Continued