" I heard the messenger of Allah say: 'When you see the crescent then fast, and when you see it, then stop fasting, and if it is obscured from you (too cloudy), then work it out (fro the beginning of the month, to complete thirty days)"'
سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ إِذَا رَأَيْتُمُ الْهِلاَلَ فَصُومُوا وَإِذَا رَأَيْتُمُوهُ فَأَفْطِرُوا فَإِنْ غُمَّ عَلَيْكُمْ فَاقْدُرُوا لَهُ