4ـ مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنِ الْحُسَيْنِ بْنِ سَعِيدٍ عَنْ عُثْمَانَ بْنِ عِيسَى عَنْ إِسْحَاقَ بْنِ عَمَّارٍ قَالَ قُلْتُ أُصَلِّي فِي وَقْتِ فَرِيضَةٍ نَافِلَةً قَالَ نَعَمْ فِي أَوَّلِ الْوَقْتِ إِذَا كُنْتَ مَعَ إِمَامٍ تَقْتَدِي بِهِ فَإِذَا كُنْتَ وَحْدَكَ فَابْدَأْ بِالْمَكْتُوبَةِ.
4. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from al-Husayn ibn Sa‘id from ‘Uthman ibn ‘Isa from Ishaq ibn ‘Ammar who has said the following: “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.’”