سنن أبي داود

Buraidah said: In the tradition telling that people with small eyes, i.e. the Turks, will fight against you, the prophet (ﷺ) said: You will drive them off three times till you catch up with them in Arabia. On the first occasion when you drive them off those who fly will be safe, on the second occasion some will be safe and some will perish, but on the third occasion they will be extirpated, or he said words to that effect.