Can ahaad hadiths be accepted with regard to ‘aqeedah?
Question

I heard someone say that ‘aqeedah cannot be proven by means of ahaad hadiths, because they are based on probability and not based on certainty. What is your response to that?.
Praise be to Allah.Our response to the one who thinks that ‘aqeedah cannot be proven on the basis of ahaad hadiths because they are based on probability or speculation and ‘aqeedah cannot be based on speculations is: This opinion is not correct, because it is based on something that is not correct. That is for a number of reasons: 
1.The idea that ahaad hadiths are based on probability or speculation does not apply in all cases; there are some ahaad hadiths that are based on certainty if there is corroborated evidence to confirm them, such as if the ummah accepted them. An example is the hadith of ‘Umar ibn al-Khattaab (may Allah be pleased with him), “Actions are but by intentions…” It is an ahaad hadith, but despite that we know that the Prophet (blessings and peace of Allah be upon him) said it. This is what was confirmed by Shaykh al-Islam Ibn Taymiyah, al-Haafiz ibn Hajar and others.
2.The Prophet (blessings and peace of Allah be upon him) used to send individuals with basic teachings of ‘aqeedah - testimony that there is no God but Allah and that Muhammad is the Messenger of Allah - and the fact that he sent them is binding proof. For example, he sent Mu‘aadh to Yemen, and the fact that he sent him is regarded as binding proof for the people of Yemen that they were obliged to accept him.
3.If we say that matters of ‘aqeedah cannot be proven on the basis of ahaad reports, then it is possible to say that practical rulings cannot be proven on the basis of ahaad reports, because practical rulings are accompanied by the belief that Allah enjoined this and forbade that. If this opinion is accepted, then many of the rulings of sharee‘ah would be rendered invalid. If this idea is rejected then the idea that ‘aqeedah cannot be proven on the basis of ahaad reports should also be rejected, because there is no difference between the two, as we have explained.
To sum up: If an ahaad report is supported by corroborating evidence which indicates that this is true, then it becomes part of knowledge and rulings of practice and belief may be established. There is nothing to indicate that there should be any differentiation between the two. Any person who suggests that any of the imams differentiated between them has to prove that with a sound chain of narration from that imam, then he has to explain his evidence.
4.Allah, may He be exalted, has enjoined referring to the people of knowledge for the one who is unaware of what is one of the most important issues of ‘aqeedah, which is Prophethood. Allah says (interpretation of the meaning):
“And We sent not (as Our Messengers) before you (O Muhammad) any but men, whom We sent Revelation, (to preach and invite mankind to believe in the Oneness of Allaah). So ask (you, O pagans of Makkah) of those who know the Scripture [learned men of the Taurat (Torah) and the Injeel (Gospel)], if you know not.
44. With clear signs and Books (We sent the Messengers)” [al-Nahl 16:43, 44]
This includes asking one or many. End quote. 
Shaykh Muhammad ibn ‘Uthaymeen (may Allah have mercy on him)