Sunan Ibn Majah 144
It was narrated from Sa'eed bin Abu Rashid that Ya'la bin Murrah told them that:
They had gone out with the Prophet to a meal to which they had been invited, and Husain was there playing in the street. The Prophet came in front of the people and stretched out his hands, and the child started to run here and there. The Prophet made him laugh until he caught him, then he put one hand under his chin and the other on his head and kissed him, and said, "Husain is part of me and I am part of him. May Allah love those who love Husain. Husain is a tribe among tribes." (Hasan)(Another chain with similar meaning)
حَدَّثَنَا يَعْقُوبُ بْنُ حُمَيْدِ بْنِ كَاسِبٍ، حَدَّثَنَا يَحْيَى بْنُ سُلَيْمٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُثْمَانَ بْنِ خُثَيْمٍ، عَنْ سَعِيدِ بْنِ أَبِي رَاشِدٍ، أَنَّ يَعْلَى بْنَ مُرَّةَ، حَدَّثَهُمْ أَنَّهُمْ، خَرَجُوا مَعَ النَّبِيِّ ـ صلى الله عليه وسلم ـ إِلَى طَعَامٍ دُعُوا لَهُ فَإِذَا حُسَيْنٌ يَلْعَبُ فِي السِّكَّةِ قَالَ فَتَقَدَّمَ النَّبِيُّ ـ صلى الله عليه وسلم ـ أَمَامَ الْقَوْمِ وَبَسَطَ يَدَيْهِ فَجَعَلَ الْغُلاَمُ يَفِرُّ هَا هُنَا وَهَا هُنَا وَيُضَاحِكُهُ النَّبِيُّ ـ صلى الله عليه وسلم ـ حَتَّى أَخَذَهُ فَجَعَلَ إِحْدَى يَدَيْهِ تَحْتَ ذَقَنِهِ وَالأُخْرَى فِي فَأْسِ رَأْسِهِ فَقَبَّلَهُ وَقَالَ ‏
"‏ حُسَيْنٌ مِنِّي وَأَنَا مِنْ حُسَيْنٍ أَحَبَّ اللَّهُ مَنْ أَحَبَّ حُسَيْنًا حُسَيْنٌ سِبْطٌ مِنَ الأَسْبَاطِ ‏"‏ ‏.‏ حَدَّثَنَا عَلِيُّ بْنُ مُحَمَّدٍ حَدَّثَنَا وَكِيعٌ عَنْ سُفْيَانَ مِثْلَهُ ‏.‏