Dought & clear - Fasting on the day of doubt .

On the night of the thirtieth of Sha'ban we went out to sight the
crescent, but the weather was cloudy so we could not see it. Should we
fast the thirtieth day of Sha'baan, because it is a day concerning
which there is some doubt?.
Praise be to Allaah.
This is what is called the "day of doubt", because there is doubt
concerning it – is it the last day of Sha'baan or the first day of
Ramadaan? Fasting on this day is haraam because the Prophet (peace and
blessings of Allaah be upon him) said, "Fast when you see the new moon
and break your fast when you see the new moon, and if you are not
sure, then complete the number of Sha'baan as thirty days." (Narrated
by al-Bukhaari, 1909).
'Ammaar ibn Yaasir said: "Whoever fasts on the day concerning which
there is doubt has disobeyed Abu'l-Qaasim (peace and blessings of
Allaah be upon him)." This was narrated by al-Tirmidhi and classed as
saheeh by al-Albaani in Saheeh al-Tirmidhi, 553.
Al-Haafiz ibn Hajar said: "It was understood from this that it is
haraam to fast the day of doubt, because the Sahaabah would not say
such a thing based on personal opinion, so a report suchas this has
the same status as a marfoo' hadeeth.
The scholars of the Standing Committee saidconcerning the day of
doubt, "The Sunnah indicates that it is haraam to fast this day."
(Fataawa al-Lajnah, 10/117)
Shaykh Muhammad ibn 'Uthaymeen (may Allaah have mercy on him)
said,after mentioning the difference of opinion concerning the ruling
onfasting the day of doubt:"The most correct of these views is that it
is haraam, but if it is proven to the ruler that it is obligatory to
fast this day and he commands the people tofast, then no one should go
against his opinion, and that means that no one should show that heis
not fasting on that day, rather a person (who has a different opinion)
may not fast, but he should do so secretly."
Al-Sharh al-Mumti', 6/318.