"The Messenger of Allah said; 'Fast when you see it and stop fasting when you see it, and if it is obscured from you (too cloudy), then complete thirty (days)."' (Using translation from Nasāʾī 2124)

قَالَ رَسُولُ اللهِ ﷺ «صُومُوا الْهِلَالَ لِرُؤْيَتِهِ وَأَفْطِرُوا لِرُؤْيَتِهِ فَإِنْ غُمَّ عَلَيْكُمْ فَأَكْمِلُوا الْعِدَّةَ ثَلَاثِينَ»