مختصر صحيح بخاري
Mukhtasar Sahih Bukhari
Prophet's command: Start and end fasting by sighting the moon.
Narrated from Umm al-Mu'mineen Umm Salamah (may Allah be pleased with her) that once the Prophet Muhammad (peace be upon him) took an oath of abstention from his pure wives for a month (i.e., swore to abstain from relations). Then, when twenty-nine days had passed, in the morning or after midday, the Prophet (peace be upon him) went to his wives. Someone said to him, "You had sworn that you would not go to your wives for a month." The Prophet (peace be upon him) replied, "A month can also be of twenty-nine days."
Both Eid months are never deficient.
Narrated by Sayyiduna Abu Bakr (may Allah be pleased with him) from the Noble Prophet (peace and blessings of Allah be upon him) that he (peace be upon him) said: "There are two months that are not reduced; both months are of Eid: (1) Ramadan (2) Dhul-Hijjah."
Prophet said: "We do not know writing or calculation."
Narrated by Sayyiduna Ibn Umar (may Allah be pleased with them both) from the Noble Prophet (peace and blessings of Allah be upon him) that he said: "We are an unlettered people; we do not know calculation. (Then, by gesturing with his fingers, he explained that) the month is like this and sometimes like this, meaning sometimes it is twenty-nine days and sometimes thirty days."
Do not fast a day or two before Ramadan.
Narrated by Sayyiduna Abu Huraira (may Allah be pleased with him) from the Noble Prophet (peace and blessings of Allah be upon him) that he (peace be upon him) said: "None of you should fast a day or two before Ramadan. However, if a person has a habit of fasting on a particular day and that day coincides (with these days), then he may fast on that day. (Specifically, it is not permissible to fast with the intention of welcoming Ramadan.)"
Allah's statement: "It is lawful for you to be intimate with your wives at night during fasting..."
Sayyiduna Bara’ (may Allah be pleased with him) says that it was the practice of the companions of Muhammad, the Messenger of Allah (peace and blessings be upon him), that when someone was fasting and, at the time of breaking the fast, slept before having iftar, then for the rest of the night he would not eat anything, nor (the next) day, until (again) evening came. And Sayyiduna Qais bin Sirmah Al-Ansari (may Allah be pleased with him) was fasting, so when the time of iftar came, he went to his wife and asked her if there was anything to eat. She said,“No, but I will go and find something.”And Qais bin Sirmah (may Allah be pleased with him) used to work hard all day, so sleep overcame him (and he fell asleep). When his wife came (with food) and saw him (sleeping), she said,“You have suffered a loss.”The next day, when it was midday, he fainted. This incident was mentioned to the Prophet (peace and blessings be upon him), so on this occasion this verse was revealed:“It has been made lawful for you to go to your wives during the nights of fasting.”The companions became extremely happy, and then these words of the verse were also revealed:“Eat and drink until the white thread (i.e., the whiteness of dawn) becomes distinct to you from the black thread of the night.”
Allah's statement: "Eat and drink until the white thread of dawn becomes distinct..."
Sayyiduna ‘Adi bin Hatim (may Allah be pleased with him) says: When the verse:“Until the white thread becomes distinct to you from the black thread...”(Surah Al-Baqarah: 187) was revealed, I took a black rope and a white rope and placed them under my pillow, and during the night I kept looking at them, but I could not discern anything. In the morning, I went to the Messenger of Allah (peace and blessings be upon him) and mentioned this to him. He said:“That (black thread) is the darkness of the night, and (white thread) is the whiteness of the morning.”
Time between suhoor and Fajr prayer.
Sayyiduna Zaid bin Thabit (may Allah be pleased with him) says: We ate suhoor with the Messenger of Allah (peace and blessings of Allah be upon him), then he stood up for prayer. (Sayyiduna Anas (may Allah be pleased with him) says, I asked him) How much time was there between the adhan and suhoor? He said: As much time as it takes to recite fifty verses.
Blessing in suhoor, but it is not obligatory.
Narrated Anas bin Malik (may Allah be pleased with him): The Prophet (peace and blessings of Allah be upon him) said: "(O people!) Eat Suhoor, for there is blessing in Suhoor. (By acting upon the command of the Messenger of Allah, there is practical benefit as well as reward in the Hereafter.)"
Intention to fast during the day.
Narrated from Sayyiduna Salamah bin Akwa’ (may Allah be pleased with him): (On one occasion) on the day of ‘Ashura, the Prophet (peace and blessings of Allah be upon him) appointed a man to announce this:“(Today) whoever has eaten something should not eat any more, and whoever has not eaten should (make the intention of fasting and) keep the fast.”
Fasting person waking up in a state of janabah (impurity).
It is narrated from Umm al-Mu'mineen Aisha Siddiqa (may Allah be pleased with her) and Umm Salamah (may Allah be pleased with her) that sometimes the Messenger of Allah (peace and blessings of Allah be upon him) would enter the morning in a state of janabah after having relations with his wives, then he would perform ghusl and observe the fast.