Praise be to Allaah.
Your vow that if you got
first place in your class, you would fast that Thursday, is an act of
worship that must be fulfilled when the condition for it is met. As you came
first in your class, you have to fast for a day as you vowed to do, because
the Prophet (peace and blessings of Allaah be upon him) said: “Whoever
vows to obey Allaah, let him obey Him.” Narrated by al-Bukhaari (6318).
It is not acceptable to
retract a vow, because of what we have stated above about it being
obligatory to fulfil it, and because ‘Umar (may Allaah be pleased with him)
said: “Four things are binding in every case: manumission, divorce,
marriage, and vows.” Narrated by Ibn Abi Shaybah in his Musannaf
(4/82). And it was narrated that ‘Ali (may Allaah be pleased with him) said:
“There are four that cannot be retracted and must be fulfilled: marriage,
divorce, manumission and vows.” This was quoted by Ibn Hazm in al-Muhalla
(8/197).
See: al-Mawsoo’ah
al-Fiqhiyyah (7/267).
Your second vow has to do
with the placing in the school; you do not have to do anything because the
condition was not fulfilled.
Based on this, if you vowed
that you would fast on any Thursday, then you must fulfil the vow.
If you vowed that you would
fast a specific Thursday and it has passed, then you have to make up this
day and fast on another Thursday, and you also have to offer expiation for
breaking an oath (kafaarat yameen), because you did not fast on the day that
you specified for fasting.
Al-Mardaawi said in
al-Insaaf (28/212):
If he vowed to fast a
certain month and he did not fast it with no excuse, then he has to make it
up and also offer expiation for breaking an oath – and there is no
difference of scholarly opinion on this point. If he did not fast it due to
an excuse, then he has to make it up – and there is no difference of
scholarly opinion on this point – but there are two opinions narrated from
Imam Ahmad with regard to expiation. Our view is that he also has to offer
expiation, and this was regarded as the correct opinion by Ibn Qudaamah and
others. End quote.
You should note that making
vows is makrooh, although it is obligatory to fulfil them, because of the
report narrated by al-Bukhaari (6608) and Muslim (1639) from Ibn ‘Umar (may
Allaah be pleased with him) who said: The Prophet (peace and blessings
of Allaah be upon him) told people not to make vows and said: “They do not
avert anything, all they do is get something out of a stingy person.”
And Allaah knows best.