Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
quran:26:97 –

"By Allah, we were indeed in manifest error  

‘By God, we had indeed (in, softened in place of the hardened form, with its subject omitted, in other words ˹it would usually be˺ innahu) been in manifest error,
القرآن:٢٦:٩٧ –

تَاللَّهِ إِنْ كُنَّا لَفِي ضَلَالٍ مُبِينٍ  

{تالله إن} مخففة من الثقلية واسمها محذوف أي إنه {كنا لفي ضلال مبين} بين.

See similar narrations below:

Collected by Qurʾān
quran:12:95 –

They said, "By Allah, indeed you are in your ˹same˺ old error."  

They said, to him: ‘By God, you are certainly in your misguidance, your error, of old’, in your excessive adoration of him, and your ˹enduring˺ hope of encountering him ˹again˺ despite the length of time ˹that has passed˺.
القرآن:١٢:٩٥ –

قَالُوا تَاللَّهِ إِنَّكَ لَفِي ضَلَالِكَ الْقَدِيمِ  

{قالوا} له {تالله إنك لفي ضلالك} خطئك {القديم} من إفراطك في محبته ورجاء لقائه على بعد العهد.