Sunnah.com reference : Book 2, Hadith 427English translation : Book 2, Hadith 497Arabic reference : Book 2, Hadith 499
Narrated Anas (RA) that when Allah's Messenger (ﷺ) came to al-Madinah, the people had two days on which they engaged in games. He (ﷺ) said:
"Allah has substituted for you something better than them: the day of sacrifice and the day of breaking the fast."

[Reported by Abu Dawud and an-Nasa'i; with a Sahih Isnad (authentic chain)].
وَعَنْ أَنَسٍ قَالَ: { قَدِمَ رَسُولُ اَللَّهِ ‏- صلى الله عليه وسلم ‏-اَلْمَدِينَةَ, وَلَهُمْ يَوْمَانِ يَلْعَبُونَ فِيهِمَا.‏ فَقَالَ: "قَدْ أَبْدَلَكُمُ اَللَّهُ بِهِمَا خَيْرًا مِنْهُمَا: يَوْمَ اَلْأَضْحَى, وَيَوْمَ اَلْفِطْرِ }  أَخْرَجَهُ أَبُو دَاوُدَ, وَالنَّسَائِيُّ بِإِسْنَادٍ صَحِيحٍ  1‏ .‏‏1 ‏- صحيح.‏ رواه أبو داود (1134)‏، والنسائي (3/179‏-180)‏.‏