[Machine] The Messenger of Allah ﷺ mentioned the sighting of the new moon and said, "When you see it, start fasting, and when you see it again, break your fast. But if it is cloudy and you are unable to see it, then complete the month as thirty days."  

ذَكَرَ رَسُولُ اللهِ ﷺ الْهِلَالَ فَقَالَ إِذَا رَأَيْتُمُوهُ فَصُومُوا وَإِذَا رَأَيْتُمُوهُ فَأَفْطِرُوا فَإِنْ أُغْمِيَ عَلَيْكُمْ فَعُدُّوا ثَلَاثِينَ  

Observe fast on sighting it (the new moon) and break (fast) on sighting it (the new moon), but if the sky is cloudy for you, then complete the number (of thirty). (Using translation from Muslim 1081b)   

قَالَ رَسُولُ اللهِ ﷺ صُومُوا لِرُؤْيَتِهِ وَأَفْطِرُوا لِرُؤْيَتِهِ فَإِنْ غُمَّ عَلَيْكُمْ فَصُومُوا ثَلَاثِينَ  

[Machine] He heard Ibn Abbas say that the Prophet of Allah ﷺ commanded us to fast upon sighting the crescent moon and to break our fast upon sighting it. But if it is cloudy and we are unable to see it, then we complete the thirty days.  

أَنَّهُ سَمِعَ ابْنَ عَبَّاسٍ يَقُولُ أَمَرَنَا رَسُولُ اللهِ ﷺ أَنْ نَصُومَ لِرُؤْيَةِ الْهِلَالِ وَنُفْطِرَ لِرُؤْيَتِهِ فَإِنْ غُمَّ عَلَيْنَا أَنْ نُكْمِلَ ثَلَاثِينَ