Concerning the voluntary prayers of the Messenger of Allah ﷺ during the day, he said, "You will not be able to keep up with them."We said, "Tell us about them anyway, and we will take from them what we can."He said, "When the Messenger of Allah ﷺ prayed Fajr, he would wait until the sun reached this point," meaning from the east, "at the same height it would be in the west at the time of Asr. Then he would stand and pray two rakahs. Then he would wait until the sun reached this point," meaning from the east, "at the height it would be at the time of Zuhr. Then he would stand and pray four rakahs. He would also pray four rakahs before Zuhr when the sun had passed its zenith, two rakahs after it, and four rakahs before Asr, separating each pair of rakahs with the salutation upon the angels brought near, the prophets, and those who followed them among the Muslims and the believers."Ali said, "That is sixteen rakahs of voluntary prayer that the Messenger of Allah ﷺ performed during the day, and few are those who maintain them regularly."Waki said, "My father added in this report that Habib bin Abu Thabit said, 'Abu Ishaq, I would not wish to have, in exchange for this hadith of yours, this mosque of yours filled with gold.'"
حدثنا علي بن محمد حدثنا وكيع حدثنا سفيان وأبي وإسرائيل عن أبي إسحق عن عاصم بن ضمرة السلولي قال
عن تطوع رسول الله ﷺ بالنهار فقال إنكم لا تطيقونه فقلنا أخبرنا به نأخذ منه ما استطعنا قال كان رسول الله ﷺ إذا صلى الفجر يمهل حتى إذا كانت الشمس من ها هنا يعني من قبل المشرق بمقدارها من صلاة العصر من ها هنا يعني من قبل المغرب قام فصلى ركعتين ثم يمهل حتى إذا كانت الشمس من ها هنا يعني من قبل المشرق مقدارها من صلاة الظهر من ها هنا قام فصلى أربعا وأربعا قبل الظهر إذا زالت الشمس وركعتين بعدها وأربعا قبل العصر يفصل بين كل ركعتين بالتسليم على الملائكة المقربين والنبيين ومن تبعهم من المسلمين والمؤمنين قال علي فتلك ست عشرة ركعة تطوع رسول الله ﷺ بالنهار وقل من يداوم عليها قال وكيع زاد فيه أبي فقال حبيب بن أبي ثابت يا أبا إسحق ما أحب أن لي بحديثك هذا ملء مسجدك هذا ذهبا
Its takhrij hasan. Tirmidhi transmitted it in the book of Jumuah, chapter on how the Prophet ﷺ used to perform voluntary prayers during the day, hadith no. 598, 599, from the hadith of Shubah, from Abu Ishaq, with this wording, and he said, "This is a hasan hadith."