Fiqh: Sawm or Siyaam (Fasting)
Part 2: The time for beginning and ending the Fast
Praise be to Allaah, we seek His help and His forgiveness. We seek refuge with Allaah from the evil of our own souls and from our bad deeds. Whomsoever Allaah guides will never be led astray, and whomsoever Allaah leaves astray, no one can guide. I bear witness that there is no god but Allaah, and I bear witness that Muhammad (peace be upon him) is His slave and Messenger.
1. The Intention (An – Niyyah)
1.1 The obligation to have intention for the obligatory fast before the appearance of the true dawn
Narrated Hafsah (may Allaah be pleased with her): The Apostle of Allaah (peace be upon him) said: “He who does not determine to fast before dawn does not fast.”
The place for the intention is the heart, to pronounce it upon the tongue is an innovation (Bid’ah) and misguidance – even if the people think it’s good.
As with Salaah, there is no verbal formula one says to mark one’s intention. To wake up for the pre – dawned meal is an expression of the intention to fast. Even if one did not wake up Suhoor, to simply make up one’s mind before sleeping that one will be fasting the nest day is sufficient.
2. The time for beginning and ending the Fast
“… and eat and drink until the white thread (light) of dawn appears to you distinct from the black thread (darkness of night), then complete your Sawm (fast) till the nightfall. …”
Narrated ‘Adi bin Hatim (may Allaah be pleased with him): When the above verses were revealed: ‘Until the white thread appears to you, distinct from the black thread,’ I took two (hair) strings, one black and the other white, and kept them under my pillow and went on looking at them throughout the night but could not make anything out of it. So, the next morning I went to Allaah’s Apostle (peace be upon him) and told him the whole story. He explained to me, “That verse means the darkness of the night and the whiteness of the dawn.” 
The fast has a specified time – with specified beginning and end – and is from the appearance of Fajr until the daytime ends, the night begins and the sins disc is hidden by the horizon.
2.1 The Two Fajrs
Narrated Ibn ‘Abbaas (may Allaah be pleased with him): The Prophet (peace be upon him) said: “The Fajr is two Fajrs: As for the first then it does not make food forbidden, nor does it make the prayer lawful. As for the second, then it makes food forbidden and the prayer lawful.”
(i) The False Dawn (al – Fajrul – Saadiq) – which does not make it lawful to pray the Fajr prayer, nor does it prohibit eating for one intending to fast.
(ii) The True Dawn (al – Fajrus – Saadiq) – which is the one which makes food forbidden for the fasting person, and makes Fajr prayer lawful.
Note that the time for Fajr prayer begins when the second dawn starts, which is the white line that spreads horizontally along the horizon right and left. The time lasts until the sun rises. The first dawn is the false dawn, which is whiteness that appears vertically in the sky like pillars. This happens approximately twenty minutes before the true dawn, and it increases and decreases according to the season.
Narrated Jaabir (may Allaah be pleased with him): The Prophet (peace be upon him) said: “There are two dawns. With regard to the dawn which is like the tail of a wolf, this does not make it permissible to pray and Haraam to eat. With regard to the dawn which appears horizontally in the sky, this makes it permissible to pray and forbidden to eat.”
Many timetables are infact inaccurate and it’s important you confirm with the local mosque that the times are correct. Sheikh al – Albaanee (may Allaah have mercy on him) said: “I have seen that myself many times in my house, in the Hamlaan mountains to the south-east of Amman, and that enables me to confirm what some of those who are keen that the Muslims’ worship should be correct have said, that the adhaan of Fajr in some Arab countries is given 20-30 minutes before the time of the true dawn, i.e., it is also before the time of the false dawn. I have often heard the iqaamah for Fajr being given in some mosques at the time when the true dawn begins, and they give the adhaan before it is time. And they may hasten to do the fard prayer before it is time during the month of Ramadaan.”
The description of the true Fajr appears in the following aayah: “…until the white thread (light) of dawn appears to you distinct from the black thread (darkness of night), then complete your Saum (fast) till the nightfall…”
Since the light of Fajr when it spreads over the mountain passes and mountain tops appears like a white thread, and a black thread appears above it – and this is the remnants of the darkness which is passing away.
So when this becomes clear to you then withhold from eating, drinking and sexual intercourse, and if there is a cup of water or a drink in your hand then drink it at ease since it is great allowance from the Most Merciful of the merciful for His fasting servants, even if you hear the adhaan. Narrated Aboo Hurayrah (may Allaah be pleased with him) said: The Messenger of Allaah (peace be upon him) said: “If one of you hears the call and the drinking vessel is in his hand then let him not put it down until he has satisfied his need from it.”
Ibn al-Qaayyim (may Allaah have mercy on him) stated that some of the salaf followed the apparent meaning of the hadeeth mentioned in the question, and they regarded it as permissible to eat and drink after hearing the adhaan of Fajr.
Then he said: But the majority are of the view that sahoor should stop when dawn breaks. This is the view of the four imams, and the majority of fuqaha’ of the regions, and was also narrated from ‘Umar and Ibn ‘Abbaas. The former quoted as evidence the words of the Prophet (peace and blessings of Allaah be upon him), Narrated ‘Abdullah bin ‘Umar (may Allaah be pleased with him): Allaah‘s Apostle (peace be upon him) said, “Bilal pronounces the Adhan at night, so keep on eating and drinking (Suhur) till Ibn Um Maktum (who was blind) pronounces the Adhan.” 
Al – Haafiz ibn Hajar (may Allaah have mercy on him) said, “One of the reprehensible innovations which have appeared in this time is to make the secondary adhaan about a third of an hour before Fajr time in Ramadaan, and the extinguishing of lights which is used as a sign indicating the forbiddance of eating and drinking for one intending to fast, claiming that what he has innovated is a precautionary measure to protect his worship – something not known except by a few individuals. This has a lead them to stage, where they do not give adhaan until four minutes or so after the actual sunset, to make sure of the time as they claim. So they delay breaking the fast and take Suhoor early and in contradiction to Sunnah, therefore there is little good found in them and much evil, and Allaah’s aid is sought.”
2.2 Then Fast Until the Night
Narrated Umar bin Al-Khattab (may Allaah be pleased with him): Allaah’s Apostle (peace be upon him) said, “When night falls from this side and the day vanishes from this side and the sun sets, then the fasting person should break his fast.”
And It is Only Allaah Who grants success. May Allaah Exalt the mention of His slave and Messenger Muhammad (peace be upon him), and render him, his household and companion safe from Evil.
– ‘Fasting In Ramadaan’, by Sheikh Saleem al – Hilaalee and ‘Alee ‘Abdul Hameed, al – Hidaayah Publishers, 1999
– ‘Islamic Studies Book 3’, by Dr. Abu Ameenah Bilal Philips, IIPH publishers, 2005
– ‘The Concise Presentation of Fiqh’, by Dr. Abdul – Azeem Badawi, IIPH, 2007
– ‘Fiqh: Volume 1’, by Muhammad Subhi ibn Hasan Hallaq, Darussalam Publishers, 2007