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:87:18 –

Indeed, this is in the former scriptures,  

Truly this, the success of those who purify themselves, and the Hereafter being better, is in the former scrolls, the ones revealed before the Qur’ān,
القرآن:٨٧:١٨ –

إِنَّ هَٰذَا لَفِي الصُّحُفِ الْأُولَىٰ  

{إن هذا} إفلاحُ من تزكى وكون الآخرة خيرا {لفي الصحف الأولى} أي المنزلة قبل القرآن.