قُلْتُ أُصَلِّي فِي وَقْتِ فَرِيضَةٍ نَافِلَةً قَالَ نَعَمْ فِي أَوَّلِ الْوَقْتِ إِذَا كُنْتَ مَعَ إِمَامٍ تَقْتَدِي بِهِ فَإِذَا كُنْتَ وَحْدَكَ فَابْدَأْ بِالْمَكْتُوبَةِ.
“I once asked him (the Imam) (a.s.), ‘Can I perform optional Salah (prayer) in the time for obligatory one?’ He (the Imam) replied, ‘Yes, you can do so in the beginning of time if you are with the Imam who leads you in Salah (prayer). If you are alone, then perform the obligatory first.’”