سَأَلْتُ أَبَا عَبْدِ اللَّهِ ع عَنِ الصَّائِمِ الْمُتَطَوِّعِ تَعْرِضُ لَهُ الْحَاجَةُ قَالَ هُوَ بِالْخِيَارِ مَا بَيْنَهُ وَ بَيْنَ الْعَصْرِ وَ إِنْ مَكَثَ حَتَّى الْعَصْرِ ثُمَّ بَدَا لَهُ أَنْ يَصُومَ فَإِنْ لَمْ يَكُنْ نَوَى ذَلِكَ فَلَهُ أَنْ يَصُومَ ذَلِكَ الْيَوْمَ إِنْ شَاءَ.
“I once asked abu ‘Abdillah (a.s.) about a man who fasts an optional fast but he faces a certain issue of his needs.“ He (the Imam) replied, ‘He has the choice until al-‘Asr (later afternoon). If he waits until al-‘Asr and then it occurs to him to fast, if he did not have the intention for fasting, he can fast that day