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:86:13 –

Indeed, the Qur'an is a decisive statement,  

assuredly it, the Qur’ān, is a decisive word, distinguishing between truth and falsehood,
القرآن:٨٦:١٣ –

إِنَّهُ لَقَوْلٌ فَصْلٌ  

{إنه} أي القرآن {لقول فصل} يفصل بين الحق والباطل.

See similar narrations below:

Collected by Abū Dāwūd
abudawud:183 – Musaddad > Muḥammad b. Jābir > Qays b. Ṭalq Biʾisnādih And Maʿnāh

"during the prayer"  

أبو داود:١٨٣ – حَدَّثَنَا مُسَدَّدٌ حَدَّثَنَا مُحَمَّدُ بْنُ جَابِرٍ عَنْ قَيْسِ بْنِ طَلْقٍ بِإِسْنَادِهِ وَمَعْنَاهُ

وَقَالَ فِي الصَّلاَةِ