Ruling on one who swears about somethingbased on what he thinksis likely to be the case, then it turns out to be otherwise

What is the ruling on one who swears by Allahabout something he does
not know? Is that halaal or haraam? Is it permissible if he is
certain? For example, if someone says to him: "Shaykh So and so did
such and such," and he replies, "No, by Allah, he did not do such and
such," even though he does not know what the shaykh did, but he is
certain that he did not do this thing or, for example, if he swears
about some matter of the unseen, what is the ruling?.
Praise be to Allaah.
One of the following scenarios must be true inthe case of the one who
swears this oath:
- Either he knows that what he is swearingto is true; in this
case his oath is true and he does not have to do anything
- or he knows that he is lying in his oath; in this case he is
sinning and committing a major sin
- or he is swearing the oath thinking it mostlikely that it is
false; in this case he is breaking his oath, even if it turns out to
be as he swore it was
- or he is swearing the oath thinking it mostlikely that it is
true; in this case he does not have to do anything, even if it turns
out to be other than what he swore to, because he only swore the oath
on the basis of what he thought, thinking that he was telling the
truth in his oath
- or he swore about something without any knowledge of it; in
this case he is sinning, because he swore an oath about something that
was unknown to him.
So if someone says, for example, that So and so did not do such and
such, because he is certain or he thinks it most likely that he did
not do it, because of what he knows about his religious commitment or
attitude, or about his situation that would prevent him from doing
that, then heis swearing on the basis of what he thinks is mostlikely
in his view. In this case there are no consequences for him from his
oath.
Al-'Imraani ash-Shaafa'i (may Allah have mercy on him) said in
al-Bayaan (10/553):
What one thinks most likely to be the case comes under the same
rulings as what one is certain about. End quote.
Al-Bukhaari (2600) and Muslim (1111) narrated that Abu Hurayrah (may
Allah be pleased with him) said:
A man came to the Messenger of Allah (blessings and peace of Allah be
upon him) and said: I am doomed! He said: "Why is that?" He said: I
had intercourse with my wife in Ramadaan. He said: "Do you have the
means to free a slave?" He said: No. He said: "Can you fastfor two
consecutive months?" He said: No. Hesaid: "Do you have the means to
feed sixty poorpersons?" He said: No. Then a man of the Ansaar brought
a large basket of dates and he (the Prophet (sa)) said: "Take this and
give it in charity." He said: Is thereanyone poorer than us, O
Messenger of Allah? By the One Who sent you with the truth, there is
no family between the two lava-fields that is more in need of it than
us. He said: "Go and feedit to your family."
Shaykh Ibn 'Uthaymeen (may Allah have mercy on him) said:
This indicates that it is permissible to swear an oath based on what
one thinks is most likely to be the case; this is based on the fact
that the man said: "By Allah, there is no family between the two lava
fields that is poorer than us." There can be no doubt this man had not
gone to every family to ask them;rather this is what he thought most
likely to bethe case and he swore an oath based on what he thought was
most likely.
End quote from Sharh al-Kaafi, 4/90
Ibn al-Qayyim (may Allah have mercy on him) said:
Al-Qaadi said: If (a person) find in his father's records that So and
so owes him a debt, it is permissible for him to claim it, on the
grounds that he thinks itmost likely that this is true. Ibn al-Qayyim
said: And he may swear an oath to that effect.
End quote from I'laam al-Muwaqqi'een, 4/129
Ibn 'Uthaymeen said:
With regard to the one who swears an oath based on what he thinksmost
likely to be the case, then it turns out to be otherwise, there is
nothing wrong with that, such as if he swore that something happened
on the basis of what he thought, then it turned out that it was not
like that – there is no sin on him for that, because he only swore the
oath based on what he thought and at the time of swearing the oath he
was sincere in what he thought most likely to be the case. Another
example is if he said: By Allah, So and so will surely come tomorrow,
or he will surely come back from his trip tomorrow, basedon what he
thinks, then that person does not come; there is no sin on him
according to the more correct opinion and he does not have to offer
expiation. That is because he only swore that oath on the basis of
what he thought.
End quote from Fataawa Noor 'ala ad-Darb, 21/2
Shaykh Saalih al-Fawzaan was asked:
What is the ruling on one who swears that something happened but he
does not know whether it happened? It so happened that we didsomething
that upset someone, and he asked our father whether we had done that
thing, butour father denied it and swore that we were innocent of
that, even though we had done it, but our father does not know. Is it
permissible for us to offer expiation without him knowing, or should
we tell him and let him offer expiation for himself, or is there no
sin in that?
He replied:
Firstly: The Muslim should guard his oaths and not hasten to swear
oaths except when necessary and when he is certain of what he is
swearing to. But if someone swears that something happened or did not
happen, based on what he thinks most likely to be the case, then it
turns out otherwise, there is no sin on him, because he swore on the
basis of what he thought was most likely to be the case. So there is
no sin on him but this is a kind of idle talk that includes an oath.
But if he swore a false oath deliberately, then he is sinning in that
case; however he does not have to offer expiation, but he has sinned
and he should ask Allah for forgiveness and repent to Him, and Allah
will accept the repentance of the one who repents. With regard to
expiation, it is not required except in the case of an oath that was
sworn with regard to something in the future that was possible.