The Virtue of al-Hasan and al-Husain, the two sons of `Ali ibn Abi Talib (raa) Sunan Ibn Majah 142

Arabic hadith text
حَدَّثَنَا أَحْمَدُ بْنُ عَبْدَةَ، حَدَّثَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، عَنْ عُبَيْدِ اللَّهِ بْنِ أَبِي يَزِيدَ، عَنْ نَافِعِ بْنِ جُبَيْرٍ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ النَّبِيَّ ـ صلى الله عليه وسلم ـ قَالَ لِلْحَسَنِ ‏"‏ اللَّهُمَّ إِنِّي أُحِبُّهُ فَأَحِبَّهُ وَأَحِبَّ مَنْ يُحِبُّهُ ‏"‏ ‏.‏ قَالَ وَضَمَّهُ إِلَى صَدْرِهِ ‏.‏
Translation
It was narrated from Abu Hurairah that

The Prophet said to Hasan: "O Allah, I love him, so love him and love those who love him." He said: "And he hugged him to his chest."