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:15:38 –

Until the Day of the time well-known."  

until the day of the known time’, the time of ˹the blowing of˺ the First Trumpet.
القرآن:١٥:٣٨ –

إِلَىٰ يَوْمِ الْوَقْتِ الْمَعْلُومِ  

{إلى يوم الوقت المعلوم} وقت النفخة الأولى.

See similar narrations below:

Collected by Qurʾān, Ṭabarānī
quran:56:50 –

Are to be gathered together for the appointment of a known Day."  

will be gathered for the tryst, the time, of a known day, that is, the Day of Resurrection.
القرآن:٥٦:٥٠ –

لَمَجْمُوعُونَ إِلَىٰ مِيقَاتِ يَوْمٍ مَعْلُومٍ  

{لمجموعون إلى ميقات} لوقت {يوم معلوم} أي يوم القيامة.
tabarani:12656 – Aḥmad b. Zakariyyā Shādhān al-Baṣrī > Kathīr b. ʿUbayd > Khālid b. Yazīd > Abū Rawq > al-Ḍaḥḥāk b. Muzāḥim > Ibn ʿAbbās

[Machine] The Messenger of Allah ﷺ said, "A middle course is never harmful."  

الطبراني:١٢٦٥٦ – حَدَّثَنَا أَحْمَدُ بْنُ زَكَرِيَّا شَاذَانُ الْبَصْرِيُّ ثنا كَثِيرُ بْنُ عُبَيْدٍ ثنا خَالِدُ بْنُ يَزِيدَ عَنْ أَبِي رَوْقٍ عَنِ الضَّحَّاكِ بْنِ مُزَاحِمٍ عَنِ ابْنِ عَبَّاسٍ قَالَ

قَالَ رَسُولُ اللهِ ﷺ «مَا عَالَ مُقْتَصِدٌ قَطُّ»