Muwatta Malik 96
موطأ مالك#96SahihYahya related to me from Malik that he had heard that Abdullah ibn Masud used to say, "Wudu is necessary if a man kisses his wife
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Salim al-HilaliMauquf Sahih
In-book reference: 2:65