Sahih Bukhari Volume 8, Book 73, Hadith Number 192.

Narated By Anas bin Malik : A man asked the Prophet “When will the Hour be established O Allah’s Apostle?” The Prophet said, “What have you prepared for it?” The man said, ” I haven’t prepared for it much of prayers or fast or alms, but I love Allah and His Apostle.” The Prophet said, “You will be with those whom you love.”