[Machine] The Messenger of Allah ﷺ said: "The likeness of one who does not complete his prayer is like that of a pregnant female camel, which carries its load until its near delivery, but then dumps it out; it neither carries its load, nor delivers its offspring. And the likeness of a person who performs the prayer is like that of a merchant who does not gain any profit until he has obtained his capital. Likewise, the voluntary prayer is not accepted until the obligatory prayer is performed, as its soundness depends on the soundness of the obligatory prayer. The earlier narrations are borne on a voluntary prayer (naflah) that is outside of the obligation, so its soundness is not based on the soundness of the obligatory prayer. And Allah knows best."  

أَنَّ رَسُولَ اللهِ ﷺ قَالَ مَثَلُ الَّذِي لَا يُتِمُّ صَلَاتَهُ كَمَثَلِ الْحُبْلَى حَمَلَتْ حَتَّى إِذَا دَنَا نِفَاسُهَا أَسْقَطَتْ فَلَا هِيَ ذَاتُ حَمْلٍ وَلَا هِيَ ذَاتُ وَلَدٍ وَمَثَلُ الْمُصَلِّي كَمَثَلِ التَّاجِرِ لَا يَخْلُصُ لَهُ رِبْحٌ حَتَّى يَخْلُصَ لَهُ رَأْسُ مَالِهِ كَذَلِكَ الْمُصَلِّي لَا تُقْبَلُ لَهُ نَافِلَةٌ حَتَّى يُؤَدِّيَ الْفَرِيضَةَ فَتَكُونُ صِحَّتُهَا بِصِحَّةِ الْفَرِيضَةِ وَالْأَخْبَارُ الْمُتَقَدِّمَةُ مَحْمُولَةٌ عَلَى نَافِلَةٍ تَكُونُ خَارِجَ الْفَرِيضَةِ فَلَا يَكُونُ صِحَّتُهَا بِصِحَّةِ الْفَرِيضَةِ وَاللهُ أَعْلَمُ  

"يَا عَلِيُّ: مَثَلُ الَّذِى لاَ يُتِمُّ صلاتَه كَمَثَلِ حُبْلَى حَمَلَتْ، فَكُلَّمَا دَنَا نِفَاسُهَا أَسْقَطَتْ، فَلاَ هِى ذَاتُ حَمْلٍ، ولاَ هِىَ ذَاتُ وِلاَدٍ، يَا عَلِيُّ: مثلُ المصَلِّى كالتَّاجِرِ لاَ يَخْلُصُ له رِبْحُه حتى يأخُذَ رأَسَ مَالِهِ، كَذَلِكَ المُصَلَّى لا تُقْبَل لَه نَافِلَة حتَّى يُؤدىَ الفَرِيضةَ".