Praise be to Allah, and peace and blessings be upon the Messenger of Allah. To proceed:
Saying “And Allah knows best” after mentioning an authentic hadith, or after explaining its meaning and ruling, is permissible. It does not indicate doubt about the authenticity of the hadith or hesitation in believing the words of the Prophet صلى الله عليه وسلم. Rather, it is an expression of proper etiquette toward Allah تعالى and an acknowledgment that the knowledge of Allah تعالى is perfect and encompasses everything.
A jurist, scholar, commentator, or narrator may say: “And Allah knows best,” while being certain about what he has transmitted or stated. This is because human knowledge, no matter how extensive it may be, remains limited in comparison with the knowledge of Allah تعالى.
Allah سبحانه وتعالى says:
“And above every possessor of knowledge is one more knowledgeable.” [Yusuf 12:76]
Ibn Abbas رضي الله عنهما said in his explanation of this verse that some people possess more knowledge than others, and Allah is above every person of knowledge.
Ikrimah رحمه الله said: “The knowledge of Allah is above everyone.”
Thus, the expression “And Allah knows best” does not mean that the speaker doubts what he has mentioned. Rather, it means that he refers absolute knowledge back to Allah تعالى and acknowledges that His knowledge is above the knowledge of all His creation.
A hadith may be authentic and firmly established from the Prophet صلى الله عليه وسلم, and a scholar may be certain of its authenticity, yet he may still say: “And Allah knows best,” because his discussion may concern other matters that could require further clarification.
For example, a jurist may reach the correct ruling, but he may omit mentioning some evidence, qualifications, or ways of resolving possible ambiguity.
A commentator may explain a hadith correctly, while some meanings of its wording or some of the chains through which the hadith was transmitted may not have come to his attention.
Likewise, a narrator may narrate a hadith according to its meaning, forget a wording that does not affect the meaning, or rely on an authentic narration while another, more complete narration also exists.
Therefore, concluding one’s statement with “And Allah knows best” is an expression of scholarly and religious etiquette, not a retraction of what was previously stated.
Imam an-Nawawi رحمه الله mentioned in the introduction to Al-Majmu' a number of etiquettes of issuing religious verdicts. He quoted as-Saymari as saying:
“He should not omit concluding his answer by saying: ‘And with Allah is success,’ or: ‘And Allah knows best,’ or: ‘And Allah is the One who grants success.’”
This indicates that saying “And Allah knows best” is a well-known expression among scholars when concluding fatwas and answers.
Indeed, Shaykh Abd al-Muhsin al-Abbad حفظه الله explained that if someone possesses knowledge of something and then says, “Allah knows best,” he has said something correct, because Allah تعالى knows more than him regardless of how extensive his knowledge may be.
No. It does not indicate doubt about an authentic hadith.
If someone says: “The Messenger of Allah صلى الله عليه وسلم said such-and-such, and Allah knows best,” the meaning is that the hadith is established as he has stated, while he acknowledges that Allah تعالى has complete knowledge of everything.
Likewise, if a scholar says: “This hadith is authentic, and its meaning is such-and-such, and Allah knows best,” this does not mean that he doubts the authenticity of the hadith. Rather, he concludes his statement by entrusting complete knowledge to Allah تعالى.
Saying “And Allah knows best” after mentioning or explaining an authentic hadith is not considered casting doubt on the hadith or failing to believe the words of the Prophet صلى الله عليه وسلم.
Rather, it is an expression of proper etiquette toward Allah تعالى and an acknowledgment that the knowledge of Allah سبحانه وتعالى encompasses everything, while human knowledge, no matter how extensive, remains limited.
For this reason, scholars have traditionally concluded their fatwas and answers by saying: “And Allah knows best,” even when they state a ruling or authenticate a hadith with certainty.
And Allah knows best.