Sahih Muslim , Book 6, Hadith 2470 (USC-MSA)

Ibn 'Abbas (Allah be pleased with him) reported that the Messenger of Allah journeyed during the month of Ramadan in a state of fasting till he reached 'Usfan. He then ordered a cup containing drinking water and he drank that openly so that the people might see it, and broke the fast (and did not resume it) till he reached Mecca. Ibn 'Abbas (Allah be pleased with him) said: Allah's Messenger fasted and broke the fast, so he who wished fasted and he who wished to break it broke it.

وَحَدَّثَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، أَخْبَرَنَا جَرِيرٌ، عَنْ مَنْصُورٍ، عَنْ مُجَاهِدٍ، عَنْ طَاوُسٍ، عَنِ ابْنِ عَبَّاسٍ، - رضى الله عنهما - قَالَ سَافَرَ رَسُولُ اللَّهِ صلى الله عليه وسلم فِي رَمَضَانَ فَصَامَ حَتَّى بَلَغَ عُسْفَانَ ثُمَّ دَعَا بِإِنَاءٍ فِيهِ شَرَابٌ فَشَرِبَهُ نَهَارًا لِيَرَاهُ النَّاسُ ثُمَّ أَفْطَرَ حَتَّى دَخَلَ مَكَّةَ ‏.‏ قَالَ ابْنُ عَبَّاسٍ - رضى الله عنهما - فَصَامَ رَسُولُ اللَّهِ صلى الله عليه وسلم وَأَفْطَرَ فَمَنْ شَاءَ صَامَ وَمَنْ شَاءَ أَفْطَرَ ‏.‏

sunnah.com