Whoever knows himself,
he knows his Lord!

{ وَلَا تَكُونُوا كَالَّذِينَ نَسُوا اللّٰهَ فَأَنسَاهُمْ أَنفُسَهُمْ أُولَٰئِكَ هُمُ الْفَاسِقُونَ }

Yes, the verse is a contrapositive proof of the truth of this saying. There are several other verses to that effect. Al-Qari quotes one of them: { and who forsakes the religion of Ibrahim save him who fools himself } (2:130); "meaning, he ignores his own soul so that he does not know its Lord." Al-Qunawi cited the verse { Say: the spirit is from my Lord, and you have been told little about it } (17:85).

Another confirmation is in the verses { We shall show them Our portents on the horizons and within themselves } (41:53) and { We verily created man and We know what his soul whispers to him, and We are nearer to him than his jugular vein } (50:16).

Another confirmation - cited by Imam al-Nawawi in his Fatawa - is the hadith "Glory to You! I cannot sufficiently extol Your praise! Truly, You are just as You have glorified Yourself!" narrated from ʿA'isha and ʿAli, Allah be well-pleased with them, in the Nine Books except al- Bukhari and al-Darimi.

This is all meaning-wise. As for Prophetic attribution, it remains unestablished as the totality of the Ulema of hadith do not accept authentication nor disauthentication of hadith on the sole basis of kashf. "Otherwise," Mulla ʿAli al-Qari said in his dictionary of forgeries, "its meaning is firmly established." I.e. it is simply not a hadith, but an aphorism which conforms with the Qur'an and Sunna.

Isnad-wise, it is more likely:

- An Israelite report in the wording, "O Man! Know yourself and you will know your Lord" cf. al-Fayruzabadi in Sifr al-Saʿada.

- A saying of Sahl al-Tustari as narrated by Abu Nuʿaym in the Hilya (10:208).

- A saying of Yahya ibn Muʿadh al-Razi as reported from Ibn al- Samʿani's Qawaʿid fi Usul al-Fiqh by al-Zarkashi in al-Tadhkira (p. 129), al-Suyuti in the Durar (p. 258 §420) and in the fatwa entitled al-Qawl al-Ashbah fi Hadithi Man ʿArafa Nafsahu fa-qad ʿArafa Rabbah in his Hawi lil-Fatawi (2:412) as well as al-Sakhawi in the Maqasid and al-Haytami in his Fatawa Hadithiyya (p. 289).

- A saying of Ibrahim ibn Ad-ham. Sharik said, "I asked Ibrahim ibn Ad-ham about what had happened between ʿAli and Muʿawiya and he wept. I felt remorse that I asked. Then he raised his head and said, 'Truly, whoever knows himself remains busy with himself and whoever knows his Lord remains busy with his Lord away from anything and anyone else.'" Narrated by Abu Nuʿaym (8:15).

Al-Mawardi mentions in his ʿAmal al-Yawm wal-Layla, as cited in Kashf al-Khafa (2:343), from ʿA'isha in Adab al-Dunya wal-Din: "The Prophet, upon him blessings and peace, was asked: 'Who among people knows his Lord best?' He replied: 'Whoever knows himself best.'" However, al- Mawardi is not among the hadith masters but an erudite and trustworthy Shafiʿi Muʿtazili qadi – and no-one else reports it.

In his Nizamiyya epistle (p. 14-16, chapter titled "What is impossible to attribute to Allah Almighty"), Imam al-Haramayn details some of the guiding principles of Ahl al-Sunna in understanding the verses and hadiths that pertain to the Divine Attributes so they steer clear of the heretical innovations of the anthropomorphists: "No attribute of which possibility (al-jawaz) forms a portion can be used to describe the exalted Godhead. For pre-eternity (qidam) and possibility are complete opposites. To elaborate: the quality of being created (al-huduth) is characterized, with regard to us, by possibility; therefore, we declare Allah transcendent above it. Being formed of parts (al-tarkib), possessing measure and form (al-taqaddur wal- tasawwur), with regard to us, is characterized by possibility. There is no combination of parts except that a hypothetical variant is also possible. Nor is there any limit (hadd), measure (qadr), length (tul), or width (ʿard) except their likes and variants are rationally possible. All these attributes, because they are possible, depend on specifications set by their Creator. Exalted is He above such attributes! This is the meaning of the statement of the liege-lord of humanity, upon him blessings and peace: 'Whoever knows himself knows his Lord.' Meaning, whoever knows himself to be utterly dependent knows his Lord's utter exemption of his own [human] attributes. For all the Names of Allah are transcendent above any signification of need and He is utterly exempt of it. Accordingly, it is obligatory to declare the transcendence of the Creator of the worlds above the least attribution of any particular direction."

Subsequent scholars reiterated the gist of the above in their explanation of this saying, some excepting the positive attribution to the Prophet, upon him blessings and peace, others, such as the Sufis (e.g. Ibn ʿAta' Allah quoting Abu al-ʿAbbas al-Mursi, Abu Talib al- Makki, and ʿIzz al-Din al-Maqdisi) focusing on content with the satisfaction that the saying undoubtedly came from the mishkat of Prophetic wisdom.

WAllahu aʿlam wa-ahkam.