Sahih Bukhari Volume 008, Book 078, Hadith Number 635.

Narated By Al-Bara 'bin 'Azib : A piece of silken cloth was given to the Prophet as a present and the people handed it over amongst themselves and were astonished at its beauty and softness. Allah's Apostle said, "Are you astonished at it?" They said, "Yes, O Allah's Apostle!" He said, "By Him in Whose Hand my soul is, the handkerchiefs of Sa'd in Paradise are better than it."