Sunan Abi Dawud — Divination and Omens (Kitab Al-Kahanah Wa Al-Tatayyur) — Hadith No: 3914
Translation
Abu Dawud said:Malik was asked about the meaning of his saying: There is no safar. He replied: The people of pre-Islamic Arabia used to make the month of safar lawful (for war). They made it lawful in one year and unlawful in another year. The Prophet (ﷺ) said: There is no safar