The Prophet of Allah, sallallaahu 'alayhi wa sallam, loved them very much:

Abu Hurayrah narrated: “I went out with the Prophet of Allah, sallallaahu 'alayhi wa sallam, during the day and we were both silent, and he went to the market of Banu Qaynuqaa' and then left, then he, sallallaahu 'alayhi wa sallam, went to the house of Faatimah. He called out: “Is Luka' [the small child, referring to Al-Hasan] there?” We thought that she was keeping Al-Hasan so she could bathe him and put a necklace on him. Then Al-Hasan came out to the Prophet of Allah, sallallaahu 'alayhi wa sallam, and they hugged each other. The Prophet of Allah, sallallaahu 'alayhi wa sallam, said: “O Allah, I love him, so love him, and love whoever loves him.” Abu Hurayrah said: “No one was more beloved to me than Al-Hasan ibn 'Ali after the Prophet of Allah, sallallaahu 'alayhi wa sallam, made this statement.”