عَنِ الْحَسَنِ، قَالَ: الدُّنْيَا ثَلَاثَةُ أَيَّامٍ: أَمَا أَمْسِ فَقَدْ ذَهَبَ بِمَا فِيهِ، وَأَمَّا غَدًا فَلَعَلَّكَ لَا تُدْرِكُهُ، وَالْيَوْمُ فَاعْمَلْ فِيهِ

Ḥasan [al-Baṣrī] (may Allāh have mercy upon him) said:

The life of this world is made up of three days: “Yesterday has gone with all that was done; tomorrow, you may never reach; but today is for you so do what you should do today.”

• Bayhayqī’s az-Zuhd al-Kabīr (477 (1/196))
• Ibn Abī Dunyā’s az-Zuhd (513-514 (1/197))