"Do not anticipate the month until you see the crescent before it, or you complete the number of days. Then fast until you see the new moon, or you complete the number of days."  

عَنْ رَسُولِ اللَّهِ ﷺ قَالَ لاَ تَقَدَّمُوا الشَّهْرَ حَتَّى تَرَوُا الْهِلاَلَ قَبْلَهُ أَوْ تُكْمِلُوا الْعِدَّةَ ثُمَّ صُومُوا حَتَّى تَرَوُا الْهِلاَلَ أَوْ تُكْمِلُوا الْعِدَّةَ قَبْلَهُ  

"The Messenger of Allah said: 'D not anticipate the month until you complete the number, or you see the crescent. Then fast, and do not stop fasting until you see the crescent, or your complete thirty days."' (Sahih) Al-Hajjaj bin Artah reported it in a Mursal from.  

عَنْ بَعْضِ أَصْحَابِ النَّبِيِّ ﷺ قَالَ قَالَ رَسُولُ اللَّهِ ﷺ لاَ تَقَدَّمُوا الشَّهْرَ حَتَّى تُكْمِلُوا الْعِدَّةَ أَوْ تَرَوُا الْهِلاَلَ ثُمَّ صُومُوا وَلاَ تُفْطِرُوا حَتَّى تَرَوُا الْهِلاَلَ أَوْ تُكْمِلُوا الْعِدَّةَ ثَلاَثِينَ أَرْسَلَهُ الْحَجَّاجُ بْنُ أَرْطَاةَ  

The Prophet ﷺ said: Do not fast (for Ramadan) before the coming of the month until you sight the moon or complete the number (of thirty days); then fast until you sight the moon or complete the number (of thirty days).  

قَالَ رَسُولُ اللَّهِ ﷺ لاَ تُقَدِّمُوا الشَّهْرَ حَتَّى تَرَوُا الْهِلاَلَ أَوْ تُكْمِلُوا الْعِدَّةَ ثُمَّ صُومُوا حَتَّى تَرَوُا الْهِلاَلَ أَوْ تُكْمِلُوا الْعِدَّةَ  

"The Messenger of Allah said: 'D not anticipate the month until you complete the number, or you see the crescent. Then fast, and do not stop fasting until you see the crescent, or your complete thirty days."' (Sahih) Al-Hajjaj bin Artah reported it in a Mursal from. (Using translation from Nasāʾī 2127)   

عَنْ بَعْضِ أَصْحَابِ رَسُولِ اللهِ ﷺ قَالَ قَالَ رَسُولُ اللهِ ﷺ لَا تَقَدَّمُوا الشَّهْرَ حَتَّى تُكْمِلُوا الْعِدَّةَ أَوْ تَرَوْا الْهِلَالَ وَصُومُوا وَلَا تُفْطِرُوا حَتَّى تُكْمِلُوا الْعِدَّةَ أَوْ تَرَوْا الْهِلَالَ  

[Machine] The Messenger of Allah ﷺ said: "Do not begin the month until you see the crescent (of the new moon) or complete the count (of days from the previous month), then fast until you see the crescent (of the new moon) or complete the count (of days). This was narrated by Jarir from Mansur, mentioned by Hudhaifah, who is trustworthy and reliable. It was also narrated by Thawri and a group of narrators from Mansur, from Rib'i, from some of the companions of the Prophet ﷺ, from the Prophet ﷺ."  

قَالَ رَسُولُ اللهِ ﷺ لَا تَقَدَّمُوا الشَّهْرَ حَتَّى تَرَوَا الْهِلَالَ أَوْ تُكْمِلُوا الْعِدَّةَ ثُمَّ صُومُوا حَتَّى تَرَوَا الْهِلَالَ أَوْ تُكْمِلُوا الْعِدَّةَ وَصَلَهُ جَرِيرٌ عَنْ مَنْصُورٍ بِذِكْرِ حُذَيْفَةَ فِيهِ وَهُوَ ثِقَةٌ حُجَّةٌ وَرَوَاهُ الثَّوْرِيُّ وَجَمَاعَةٌ عَنْ مَنْصُورٍ عَنْ رِبْعِيٍّ عَنْ بَعْضِ أَصْحَابِ النَّبِيِّ ﷺ عَنِ النَّبِيِّ ﷺ  

"لا تَقَدَّمُوا الشَّهْرَ حَتَّى تَروا الهِلالَ أو تكملوا العِدَّةَ قَبْلَهُ ثم صُومُوا حَتَّى تَرَوا الهِلال. أَوْ تُكْمِلُوا العِدَّةَ قَبْلَهُ".