Oaths and Vows (Kitab Al-Aiman Wa Al-Nudhur)

Dawud :: Book 21 : Hadith 3252

Narrated Buraydah ibn al-Hasib:

The Prophet (peace_be_upon_him) said: If anyone takes an oath and says: I am free from Islam; now if he is a liar (in his oath), he will not return to Islam with soundness.