Abu Dawud
Purification (Kitab Al-Taharah)
Book Number: 001 / Hadith Number: 178
Narated By 'Aisha, Ummul Mu'minin : The Prophet (pbuh) kissed me and did not perform ablution.
Abu Dawud said: this tradition is Mursal (i.e. when the link of Companions is missing and the successor reports from the Prophet directly). Ibrahim al-Taimi did not hear anything from 'Aisha.
Abu Dawud said: Al-Firyabi and others narrated this tradition in a like manner.