Sahih Bukhari Volume 8, Book 73, Hadith Number 22.

Narated By Sa’id : Um Khalid bint Khalid bin Said said, “I came to Allah’s Apostle along with my father and I was wearing a yellow shirt. Allah’s Apostle said, “Sanah Sanah!” (‘Abdullah, the sub-narrator said, “It means, ‘Nice, nice!’ in the Ethiopian language.”) Um Khalid added, “Then I started playing with the seal of Prophet hood. My father admonished me. But Allah’s Apostle said (to my father), “Leave her,” Allah’s Apostle (then addressing me) said, “May you live so long that your dress gets worn out, and you will mend it many times, and then wear another till it gets worn out (i.e. May Allah prolong your life).” (The sub-narrator, ‘Abdullah aid, “That garment (which she was wearing remained usable for a long period).”