Reward for fasting is up to Allah for the servant restrains himself from his bodily desires

Messenger of Allah ﷺ said, "Fasting is a shield (or a screen or a shelter). So, the person observing fasting should avoid sexual relation with his wife and should not behave foolishly and impudently, and if somebody fights with him or abuses him, he should tell him twice, 'I am fasting."

The Prophet ﷺ added, "By Him in Whose Hands my soul is, the smell coming out from the mouth of a fasting person is better in the sight of Allah than the smell of musk. (Allah says about the fasting person), 'He has left his food, drink and desires for My sake. The fast is for Me. So I will reward (the fasting person) for it and the reward of good deeds is multiplied ten times."  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ: «الصِّيَامُ جُنَّةٌ: فَلاَ يَرْفُثْ، وَلاَ يَجْهَلْ؛ وَإِنِ امْرُؤٌ قَاتَلَهُ أَوْ شَاتَمَهُ فَلْيَقُلْ: إِنِّي صَائِمٌ مَرَّتَيْنِ۔»

«وَالَّذِي نَفْسِي بِيَدِهِ لَخُلُوفُ فَمِ الصَّائِمِ أَطْيَبُ عِنْدَ اللَّهِ تَعَالَى مِنْ رِيحِ الْمِسْكِ: يَتْرُكُ طَعَامَهُ، وَشَرَابَهُ، وَشَهْوَتَهُ مِنْ أَجْلِي؛ الصِّيَامُ لِي وَأَنَا أَجْزِي بِهِ وَالْحَسَنَةُ بِعَشْرِ أَمْثَالِهَا۔»  

Allah, the Majestic and the Exalted, said: Every act of the son of Adam is for him except fasting. It is done for My sake, and I will give a reward for it. By Allah in Whose Hand is the life of Muhammad, the breath of the observer of fast is sweeter to Allah than the fragrance of musk.  

سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ قَالَ اللَّهُ ﷻ كُلُّ عَمَلِ ابْنِ آدَمَ لَهُ إِلاَّ الصِّيَامَ هُوَ لِي وَأَنَا أَجْزِي بِهِ فَوَالَّذِي نَفْسُ مُحَمَّدٍ بِيَدِهِ لَخِلْفَةُ فَمِ الصَّائِمِ أَطْيَبُ عِنْدَ اللَّهِ مِنْ رِيحِ الْمِسْكِ  

"Allah, may He be blessed and exalted, says: 'Fasting is for me and I shall reward for it. The fasting person has two moments of joy: When he breaks his fast and when he meets his Lord.' By the One in whose hand is my soul, the smell that comes from the mouth of the fasting person is better before Allah than the fragrance of musk." '  

عَنْ رَسُولِ اللَّهِ ﷺ قَالَ إِنَّ اللَّهَ تَبَارَكَ وَتَعَالَى يَقُولُ الصَّوْمُ لِي وَأَنَا أَجْزِي بِهِ وَلِلصَّائِمِ فَرْحَتَانِ حِينَ يُفْطِرُ وَحِينَ يَلْقَى رَبَّهُ وَالَّذِي نَفْسِي بِيَدِهِ لَخُلُوفُ فَمِ الصَّائِمِ أَطْيَبُ عِنْدَ اللَّهِ مِنْ رِيحِ الْمِسْكِ  

"The Prophet said: 'Allah, may He be blessed and exalted, says: Fasting is for me I shall reward for it. The fasting person has two moments of joy: When he breaks his fast and when he meets his Lord. By the One in Whose hand is the soul of Muhammad, the smell that comes from the mouth of the fasting person is better before Allah than the fragrance of musk." '  

قَالَ النَّبِيُّ ﷺ إِنَّ اللَّهَ تَبَارَكَ وَتَعَالَى يَقُولُ الصَّوْمُ لِي وَأَنَا أَجْزِي بِهِ وَلِلصَّائِمِ فَرْحَتَانِ إِذَا أَفْطَرَ فَرِحَ وَإِذَا لَقِيَ اللَّهَ فَجَزَاهُ فَرِحَ وَالَّذِي نَفْسُ مُحَمَّدٍ بِيَدِهِ لَخُلُوفُ فَمِ الصَّائِمِ أَطْيَبُ عِنْدَ اللَّهِ مِنْ رِيحِ الْمِسْكِ  

"Fasting is a shield against the Fire. Whoever starts the day of fasting, let him not act in an ignorant manner during that day. If anyone treats him in an ignorant maner, let him not insult him or curse him, rather let him say: "I am fasting.' By the One in whole hand is the soul of Muhammad, the smell that comes from the mouth of a fasting person is better before Allah than the fragrance of musk."  

عَنِ النَّبِيِّ ﷺ قَالَ الصِّيَامُ جُنَّةٌ مِنَ النَّارِ فَمَنْ أَصْبَحَ صَائِمًا فَلاَ يَجْهَلْ يَوْمَئِذٍ وَإِنِ امْرُؤٌ جَهِلَ عَلَيْهِ فَلاَ يَشْتِمْهُ وَلاَ يَسُبَّهُ وَلْيَقُلْ إِنِّي صَائِمٌ وَالَّذِي نَفْسُ مُحَمَّدٍ بِيَدِهِ لَخُلُوفُ فَمِ الصَّائِمِ أَطْيَبُ عِنْدَ اللَّهِ مِنْ رِيحِ الْمِسْكِ  

"The Prophet said: 'Allah, may He be blessed and exalted, says: Fasting is for me I shall reward for it. The fasting person has two moments of joy: When he breaks his fast and when he meets his Lord. By the One in Whose hand is the soul of Muhammad, the smell that comes from the mouth of the fasting person is better before Allah than the fragrance of musk." ' (Using translation from Nasāʾī 2213)   

قَالَ رَسُولُ اللهِ ﷺ إِنَّ اللهَ يَقُولُ إِنَّ الصَّوْمَ لِي وَأَنَا أَجْزِي بِهِ إِنَّ لِلصَّائِمِ فَرْحَتَيْنِإِذَا أَفْطَرَ فَرِحَ وَإِذَا لَقِيَ اللهَ فَجَزَاهُ فَرِحَ وَالَّذِي نَفْسُ مُحَمَّدٍ بِيَدِهِ لَخُلُوفُ فَمِ الصَّائِمِ أَطْيَبُ عِنْدَ اللهِ مِنْ رِيحِ الْمِسْكِ  

[Machine] And the Messenger of Allah ﷺ said, "By the One in whose hand is the soul of Muhammad, the breath of the fasting person is sweeter to Allah than the fragrance of musk. The fasting person abstains from their desires, food, and drink for My sake, and I will reward them for it."  

وَقَالَ رَسُولُ اللهِ ﷺ وَالَّذِي نَفْسُ مُحَمَّدٍ بِيَدِهِ لَخُلُوفُ فَمِ الصَّائِمِ أَطْيَبُ عِنْدَ اللهِ مِنْ رِيحِ الْمِسْكِ يَذَرُ شَهْوَتَهُ وَطَعَامَهُ وَشَرَابَهُ مِنْ جَرَّايَ فَالصِّيَامُ لِي وَأَنَا أَجْزِي بِهِ  

[Machine] The Prophet ﷺ said, "Do not curse while you are fasting. If someone curses you, say: 'I am fasting.' And if you are standing, then sit down. By the One in Whose hand is the soul of Muhammad, the breath of the fasting person is more fragrant to Allah than the scent of musk."  

عَنِ النَّبِيِّ ﷺ قَالَ لَا تَسَابَّ وَأَنْتَ صَائِمٌفَإِنْ سَبَّكَ أَحَدٌ فَقُلْ إِنِّي صَائِمٌ وَإِنْ كُنْتَ قَائِمًا فَاقْعُدْ وَالَّذِي نَفْسُ مُحَمَّدٍ بِيَدِهِ لَخُلُوفُ فَمِ الصَّائِمِ أَطْيَبُ عِنْدَ اللهِ مِنْ رِيحِ الْمِسْكِ  

Allah, the Exalted and Majestic, said: Fast (is exclusively) meant for Me and I would give its reward. There are two (occasions) of joy for the observer of fast. He feels joy when he breaks the fast and he is happy when he meets Allah. By Allah in Whose Hand is the life of Muhammad, the breath of the observer of fast is sweeter to Allah than the fragrance of musk. (Using translation from Muslim 1151f)   

"إِنَّ الله ﷻ يقولُ إِنَّ: الصومَ لِيَ، وَأنَا أجْزِى بِهِ. إِن

لِلصائم فَرْحَتَين إِذَا أفْطَرَ فَرِحَ، وَإذا لَقِيَ الله فجزاهُ فَرحَ، والذي نَفْسُ مُحَمدٍ بِيَدِهِ لَخُلُوفُ فَم الصائِم أطيَبُ عِنْدَ الله مِنْ ريحِ المِسْكِ".  

"الصِّيَامُ جُنَّةٌ مِنَ النَّارِ، فَمَنْ أَصْبَحَ صَائِمًا فَلَا يَجْهَل يَوْمئِذ، وَإِنِ امْرُؤٌ جَهِلَ عَلَيهِ فَلَا يَشْتُمْهُ وَلَا يَسُبَّهُ وَلْيَقُلْ إِنِّي صَائِمٌ، والَّذِى نَفسُ مُحَمَّد بيَدِهِ لَخُلُوفُ فَم الصَّائم أَطْيَبُ عِنْدَ الله مِنْ رِيح الْمِسْكِ ".  

"عن علىٍّ عنِ النبىِّ ﷺ قَالَ: إِنَّ الله يَقُولُ: الصَّوْمُ لِى وَأَنَا أَجْزِى بِهِ، وَللصَّائِمِ فَرْحَتَانِ عِنْدَ الْفِطْرِ، وَحِينَ يَلْقَى رَبَّهُ - ﷻ - وَالَّذِى نَفْسُ مُحَمَّدٍ بِيَدِهِ لَخَلُوفُ فَمِ الصَّائِمِ أَطْيَبُ عِنْدَ الله مِنْ رِيحِ الْمِسْكِ".  

"إِنَّ ربَّكم يقولُ: كلُّ حَسَنة بِعشْرِ أَمْثَالِهَا إِلى سبعِمائة ضعفٍ والصومُ لِى وأَنَا أَجْزِى به، والصومُ جُنَّةٌ من النَّارِ، وَلَخَلُوفُ فَمِ الصائِم أَطْيَبُ عندَ اللَّهِ من ريحِ المسكِ، وإِن جَهِلَ على أَحدِكم جاهلٌ، وهو صائمٌ فليقل: إِنِّى صائم".