Fast thirty days of Ramadan if one is unable to see the moon

Whenever you sight the new moon (of the month of Ramadan) observe fast. and when you sight it (the new moon of Shawwal) break it, and if the sky is cloudy for you, then observe fast for thirty days.  

قَالَ رَسُولُ اللَّهِ ﷺ إِذَا رَأَيْتُمُ الْهِلاَلَ فَصُومُوا وَإِذَا رَأَيْتُمُوهُ فَأَفْطِرُوا فَإِنْ غُمَّ عَلَيْكُمْ فَصُومُوا ثَلاَثِينَ يَوْمًا  

"When you see the crescent then fast, and when you crescent then fast, and when you see it, stop fasting. If it is obscured from you (too cloudy), then fast thirty days."  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ إِذَا رَأَيْتُمُ الْهِلاَلَ فَصُومُوا وَإِذَا رَأَيْتُمُوهُ فَأَفْطِرُوا فَإِنْ غُمَّ عَلَيْكُمْ فَصُومُوا ثَلاَثِينَ يَوْمًا  

“When you see the new crescent then fast, and when you see it then stop fasting. If it is cloudy then fast thirty days.”  

قَالَ رَسُولُ اللَّهِ ﷺ إِذَا رَأَيْتُمُ الْهِلاَلَ فَصُومُوا وَإِذَا رَأَيْتُمُوهُ فَأَفْطِرُوا فَإِنْ غُمَّ عَلَيْكُمْ فَصُومُوا ثَلاَثِينَ يَوْمًا  

“When you see the new crescent then fast, and when you see it then stop fasting. If it is cloudy then fast thirty days.” (Using translation from Ibn Mājah 1655)  

أَنَّ رَسُولَ اللهِ ﷺ قَالَ إِذَا رَأَيْتُمُ الْهِلَالَ فَصُومُوا وَإِذَا رَأَيْتُمُوهُ فَأَفْطِرُوا فَإِنْ غُمَّ عَلَيْكُمْ فَصُومُوا ثَلَاثِينَ يَوْمًا  

“When you see the new crescent then fast, and when you see it then stop fasting. If it is cloudy then fast thirty days.” (Using translation from Ibn Mājah 1655)  

قَالَ رَسُولُ اللهِ ﷺ إِذَا رَأَيْتُمُ الْهِلَالَ فَصُومُوا وَإِذَا رَأَيْتُمُوهُ فَأَفْطِرُوا فَإِنْ غُمَّ عَلَيْكُمْ فَصُومُوا ثَلَاثِينَ يَوْمًا  

“When you see the new crescent then fast, and when you see it then stop fasting. If it is cloudy then fast thirty days.” (Using translation from Ibn Mājah 1655)  

قَالَ رَسُولُ اللهِ ﷺ إِذَا رَأَيْتُمُ الْهِلَالَ فَصُومُوا وَإِذَا رَأَيْتُمُوهُ فَأَفْطِرُوا فَإِنْ غُمَّ عَلَيْكُمْ فَصُومُوا ثَلَاثِينَ يَوْمًا  

“When you see the new crescent then fast, and when you see it then stop fasting. If it is cloudy then fast thirty days.” (Using translation from Ibn Mājah 1655)  

أَنَّ رَسُولَ اللهِ ﷺ قَالَ «إِذَا رَأَيْتُمُ الْهِلَالَ فَصُومُوا وَإِذَا رَأَيْتُمُوهُ فَأَفْطِرُوا فَإِنْ غُمَّ عَلَيْكُمْ فَصُومُوا ثَلَاثِينَ يَوْمًا»  

"The Messenger of Allah said: 'When you see the crescent then fast, and when you see it, then stop fasting. If it is too cloudy then complete Shaban as thirty days, unless you see the crescent before that, then fast Ramadan as thirty days, unless you see the new crescent before that."' (Using translation from Nasāʾī 2128)  

قَالَ رَسُولُ اللهِ ﷺ «إِذَا رَأَيْتُمُ الْهِلَالَ فَصُومُوا وَإِذَا رَأَيْتُمُوهُ فَأَفْطِرُوا فَإِنْ غُمَّ عَلَيْكُمْ فَأَتِمُّوا ثَلَاثِينَ أَتِمُّوا شَعْبَانَ ثَلَاثِينَ إِلَّا أَنْ تَرَوُا الْهِلَالَ قَبْلَ ذَلِكَ ثُمَّ صُومُوا رَمَضَانَ ثَلَاثِينَ إِلَّا أَنْ تَرَوُا الْهِلَالَ قَبْلَ ذَلِكَ»