A person may receive only a fraction of his prayer

[AI] Ammar prayed two rakahs, and Abd al-Rahman ibn al-Harith said to him, "O Abu al-Yaqzan, I only see that you have made them brief." He said, "Have I reduced anything of their required parts?" He said, "No, but you made them brief." He said, "I hastened through them because of forgetfulness; I heard the Messenger of Allah ﷺ say: "A man may pray, yet perhaps he will have from his prayer only a tenth of it, a ninth of it, or an eighth of it, or a seventh of it"." He continued until he reached the end of the count.

أَنَّ عَمَّارًا صَلَّى رَكْعَتَيْنِ، فَقَالَ لَهُ عَبْدُ الرَّحْمَنِ بْنُ الْحَارِثِ: يَا أَبَا الْيَقْظَانِ، لَا أَرَاكَ إِلَّا قَدْ خَفَّفْتَهُمَا. قَالَ: هَلْ نَقَصْتُ مِنْ حُدُودِهَا شَيْئًا؟ قَالَ: لَا، وَلَكِنْ خَفَّفْتَهُمَا. قَالَ: إِنِّي بَادَرْتُ بِهِمَا السَّهْوَ، إِنِّي سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ: «إِنَّ الرَّجُلَ لَيُصَلِّي، وَلَعَلَّهُ أَنْ لَا يَكُونَ لَهُ مِنْ صَلَاتِهِ إِلَّا عُشْرُهَا، وَتُسْعُهَا، أَوْ ثُمُنُهَا، أَوْ سُبُعُهَا». حَتَّى انْتَهَى إِلَى آخِرِ الْعَدَدِ.

[Machine] I heard the Messenger of Allah ﷺ say, "Indeed, a person may pray, and perhaps he will not have from his prayer except one-tenth of it, or one-ninth of it, or one-eighth of it, or one-seventh of it, until he reaches the last count."

سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ «إِنَّ الرَّجُلَ لَيُصَلِّي وَلَعَلَّهُ أَنْ لَا يَكُونَ لَهُ مِنْ صَلَاتِهِ إِلَّا عُشْرُهَا أَوْ تُسْعُهَا أَوْ ثُمْنُهَا أَوْ سُبْعُهَا حَتَّى انْتَهَى إِلَى آخِرِ الْعَدَدِ»

اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ إِنَّ الرَّجُلَ لِيُصَلِّي الصَّلَاةَ وَلَعَلَّهُ أَنْ لَا تَكُونَ لَهُ مِنْ صَلَاتِهِ إِلَّا عُشْرُهَا تُسْعُهَا ثُمُنُهَا سُبُعُهَا سُدُسُهَا خُمُسُهَا حَتَّى انْتَهَى إِلَى آخِرِ الْعَدَدِ