On the authority of Abu Masood Uqbah bin 'Amr al-Ansaree al-Badree (may Allah be pleased with him) who said:
The Messenger of Allah (peace and blessings of Allah be upon him) said, "Verily, from what was learnt by the people from the speech of the earliest prophecy is: If you feel no shame, then do as you wish."[Al-Bukhari]
Reference: 40 Hadith Nawawi 20
English translation: Hadith 20