Why do we count the age of Islam from the beginning of the Hijrah and not from the beginning of the revelation and the call?

I hope insha allah this question reaches u in good health. My question is I have noticed when a non muslim asks about the age islam after prophet hood we as Muslims answer only withthe years after hijrah, my question is why do we always leave out the first 13 years of prophet hood before hijrah. I know the year of Hijrah was a great year yet we all know that prophet hood started 13 years before this so when answering why dont we mention this like now we are 1433 AH yet when answering why dont we say islam after prophet hood is 1446 adding the 13 years before the period. insha allah you can explain why we dont add the first 13 years into our answer.
Praise be to Allaah.
No doubt the years that the Prophet (blessings and peace of Allah be upon him) spent in Makkah before the Hijrah (migration to Madinah), when he was calling people to the path of his Lord, enduring persecution and patiently putting up with the annoyance and accusations of the foolish, could is part of the age of Islam; indeed they are among the greatest years of Islam because during this time the Prophet (blessings and peace of Allah be upon him) was relying completely upon his Lord, thinking positively of Him, and patiently bearing persecution for His sake.
This is something that no wise person would doubt and no one would deny it at all, whether he is Muslim or otherwise.
But the reason why the people adopted the Hijri calendar as a means of defining the year in whicha particular event took place, which is something that people need to do, is that this date is the one that the Sahaabah unanimously agreed to take as the beginning of their calendar. This decision was made at the time of ‘Umar ibn al-Khattaab (may Allah be pleased with him), because it is the actual date of the founding of the Islamic state, when the Prophet (blessings and peace of Allah be upon him) and migrated and settled in Madinah, and the people gathered around him and supported him, and he built the mosque, and other events that followed the Hijrah. So the features of the Islamicstate began to develop and it took on a clear form geographically, socially, militarily and politically. Before that the Muslims did not have a state or any political system to unite them.
The Sahaabah (may Allah be pleased with them) reached a unanimous decision in 16 AH – or, it was said, 17 AH or 18 AH – during ‘Umar’s caliphate,to make the Islamic calendar begin with the year in which the Hijrah occurred. That was because a case was referred to Ameer al-Mu’mineen ‘Umar (may Allah be pleased with him) concerning a contract that one man had with another, saying that what he owed him became due in Sha‘baan.
‘Umar said; Which Sha‘baan? The Sha‘baan ofthis year we are in now orof last year or of next year? Then he summonedthe Sahaabah and consulted them about adopting a calendar from which they could determine when debts became due and the like.
Someone suggested adopting the Persian calendar, but he did not like that. Someone else suggested adopting the Byzantine calendar, but he did not like that. Others suggested dating itfrom the birth of the Messenger of Allah (blessings and peace of Allah be upon him), or from the beginning of his mission, or from his migration (Hijrah) or fromhis death.
‘Umar (may Allah be pleased with him) was inclined to choose the date of the Hijrah becauseit is known when it occurred, and they agreedwith him.
The point is that they made the beginning of the Islamic calendar the year of the Hijrah, and they made the first monthof the Islamic year Muharram, as was narrated from them. This is the view of the majorityof imams, so that people could conduct their business on that basis, with no confusion.
See: al-Bidaayah wa’n-Nihaayah, 3/251-253
Al-Bukhaari narrated in his Saheeh (3934) that Sahl ibn Sa‘d said: They did not start the calendar from the beginning of theProphet’s mission or from his death; they only started it from the time ofhis arrival in Madinah.
Al-Haafiz Ibn Hajar (may Allah have mercy on him) said:
The incidents that are connected to the life of the Prophet (blessings and peace of Allah be upon him) and that could have been taken as the start of the calendar are four: his birth, the start of his mission, his migration (Hijrah) and his death. They thought it was best to start the calendar from the Hijrah,
/ - - - :-> Transtors: 1.http://free-translation.imtranslator.net/lowres.asp 2.http://translate.google.com/m?twu=1&hl=en&vi=m&sl=auto&tl=en

4a] When should one stop eating and drinking? And what is the ruling on one who has the vessel in his hand when hearing the adhaan?

4a]
Shaykh Ibn 'Uthaymeen (may Allah have mercy onhim) was asked: When
should a person stop eating? Is it as they say: when the muezzin says
Laa ilaaha ill-Allaah? Whatis the ruling if he drinks deliberately
after the adhaan? Is he like the onewho drinks after 'Asr or can he
still fast? Some people say that Fajr is not like a lamp which shines
instantly and the matter is broad in scope. What is the ruling?
He replied: If the muezzin gives the call to prayer when the dawn has
come,then the Prophet (blessings and peace of Allah be upon him) said:
"Eat and drink until Ibn Umm Maktoom gives the call to prayer, because
he does not give the call to prayer until dawn breaks." So if the
muezzin says: I have seen the dawn and I do not give the call to
prayer until I see the dawn, then it is obligatory for one to stop
eating and drinking from the moment he hears the adhaan, except in the
casein which a concession is allowed, which is if the vessel is in his
hand, in which case he may drink what he needs of it. But if the
adhaan is given according to a timetable, then the timetable in fact
is not connected to the actual times, rather it is based on
calculations -- the timetables that we have now for Umm al-Qura
[Makkah] or other cities are based on calculations, because they do
not look at the dawn or the sun or the meridianor the time when 'Asr
begins or the setting of the sun. End quote. Al-Liqa' al-Shahri, 1/214
To sum up: one should stop eating and drinking etc as soon as he hears
the adhaan, if he knows that the muezzin gives the call on time. But
if he is not sure about that, then he should limit it to drinking what
is in his hand, because it cannot be said that he may continue eating
and drinking until he is certainthat dawn has broken. In fact, he has
no means of ascertaining whether dawn has come because of lights and
electricity, and many people are unable to distinguish between the
true dawn and the false dawn.
And Allah knows best.

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4] When should one stop eating and drinking? And what is the ruling on one who has the vessel in his hand when hearing the adhaan?

4] When should one stop eating and drinking? And what is the ruling on
one who has the vessel in his hand when hearing the adhaan?
~
When exactly must one stop eating and drinking if one is going to
fast? Is itthe adhaan of Fajr when the muezzin says Allaahu akbar, or
what is the exact time? What should Ido if the cup is at my mouth and
I am drinking and the call to prayer begins?.
Praise be to Allaah.
With regard to fasting, it is obligatory to refrain from things that
break the fast from the onset of the true dawn, until the sun sets.
Allah says (interpretation of the meaning):
"So now have sexual relations with them and seek that which Allaah has
ordained for you (offspring), 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"
[al-Baqarah 2:187].
Al-Bukhaari (1919) narrated from 'Aa'ishah (may Allah be pleased with
her) that Bilaal used to give the adhaan at night. The Messenger of
Allah (blessings and peaceof Allah be upon him) said: "Eat and drink
until Ibn Umm Maktoom gives the call to prayer, becausehe does not
give the call to prayer until dawn breaks."
Based on that, if a person knows that the true dawnhas broken, either
by seeing it himself or because someone else hastold him, then he must
stop eating and drinking. If he hears the call to prayer, he must stop
eating and drinking as soon as he hears it, if the muezzin give the
call on time and not ahead of time.
Some scholars made an exception if a person has the cup in his hand
when he hears the adhaan, and said that he may drink what he needs
from it, because of the report narrated by Abu Dawood (2350) from Abu
Hurayrah(may Allah be pleased with him) said: The Messenger of Allah
(blessings and peace of Allah be upon him) said: "When one if you
hears the call and the vessel is in his hand, let him not put it down
until he has fulfilled his need of it." Al-Albaani said in Saheeh Abi
Dawood: Its isnaad is hasan saheeh. It was also classed as saheeh by
al-Haakim, al-Dhahabi and'Abd al-Haqq al-Ishbeeli, and Ibn Hazm quoted
it asevidence. End quote.
The majority of scholars interpreted it as meaning that the muezzin
used to give the call to prayer ahead of time. For a detailed
discussion on that, please see the answer to question number 66202 .
Most of the muezzins nowadays rely on clocks and timetables, not on
actual sighting of the dawn, but this cannot be regarded as certainty
thatdawn has broken, so if a person is still eating at this time, his
fast is valid because he was not certain that dawn had broken. But it
is better and more on the safe sideto refrain from things thatbreak
the fast when one hears the adhaan.
Shaykh 'Abd al-'Azeez ibn Baaz (may Allah have mercy on him) was
asked:What is the shar'i ruling on the fast of one who hears the
adhaan of Fajr and continues eating and drinking?
He replied: What the believer must do is refrainfrom eating and
drinking and other things that break the fast as soon as it becomes
clear to him that dawn has broken, if the fast is an obligatory fast
such as Ramadan or fasting in fulfilment of a vow or as expiation,
because Allah says (interpretation of the meaning):
"and eat and drink until the white thread (light) ofdawn appears to
you distinct from the black thread (darkness of night),then complete
your Sawm(fast) till the nightfall"
[al-Baqarah 2:187].
So if he hears the adhaan and knows that the call is being given at
the time ofdawn, then he must stop eating and drinking. But ifthe
muezzin gives the adhaan before dawn breaks, he does not have to stop
eating and drinking and it is permissible for him to carry on eating
and drinking until he sees the dawn.
If he does not know whether the muezzin gives the call to prayer
before or after dawn, thenit is better and more on the safe side to
stop eating and drinking whenhe hears the call to prayer, but it does
not matter if he ate or drank something at the time of the adhaan,
because he did not know whether dawn had broken.
It is well known that people living in cities in which there are
streetlights cannot see the break of dawn for themselves at the time
of dawn. But they should be on the safe side by using the adhaan and
timetables which give thetime of dawn to the hour and minute,
following thewords of the Prophet (blessings and peace of Allah be
upon him): "Leave that which makes you doubt for that which does not
make you doubt" and "Whoever avoids dubious matters will have kept his
religious commitment and honour safe." And Allah is the source of
strength. End quote from Fataawa Ramadaan, compiled by Ashraf 'Abd
al-Maqsood, p. 201. ...

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Eating out of forgetfulness in Ramadan does not matter

What is the ruling on one who eats or drinks out of forgetfulness
during Ramadan?
Praise be to Allaah.
That does not matter and his fast is valid, because Allaah says at the
end of Soorat al-Baqarah (interpretation of the meaning):
"Our Lord! Punish us not ifwe forget or fall into error"
[al-Baqarah 2:286]
It was narrated in a saheeh report from the Messenger of Allaah (peace
and blessings of Allaah be upon him) that Allaah said, "I have done
that." And it was narrated from Abu Hurayrah (may Allaah be pleased
with him) that the Prophet (peace and blessings of Allaah be upon him)
said: "Whoever forgets that he is fasting and eats or drinks, let him
complete his fast, for the One Who fed him and gave him to drink was
Allaah." (Agreedupon).
The same applies if he hasintercourse because of forgetfulness; his
fast is still valid according to the more correct of the two scholarly
opinions, because of this aayah and this hadeeth, and becausethe
Prophet (peace and blessings of Allaah be upon him) said:
"Whoeverbreaks his fast in Ramadaan out of forgetfulness, he does
nothave to make that day up and he does not have to offer any
expiation (kafaarah)." (Narrated andclassed as saheeh by al-Haakim).
This wording includes intercourse and other things that break the
fast, if the fasting person does them because of forgetfulness. This
is from the mercy, bounty and kindness of Allaah, for which we praise
and thank Him.
Majmoo' Fataawa al-Shaykh Ibn Baaz, vol. 4, p. 193.

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