Balak king of Moab, terrified by Israel's victories, sent for the prophet-diviner Balaam to come and curse Israel. After initial refusal, Balaam set out on his donkey. The angel of the LORD stood in the road with a drawn sword to oppose him — visible only to the donkey, not to the prophet. Three times the donkey turned aside (into a field, against a wall, and finally simply lying down under Balaam) to avoid the angel; three times Balaam beat her.
The LORD opened the mouth of the donkey: 'What have I done to you, that you have struck me these three times?' Balaam, mid-argument, only then noticed that he was conversing with an animal. The LORD then opened Balaam's eyes; he saw the angel and the drawn sword and fell on his face. Continuing his journey, Balaam was given three times to curse Israel, and three times — to Balak's fury — God forced him to bless Israel instead. His final oracle includes the messianic prophecy of 'a star that shall come forth out of Jacob' (Num 24:17), read by Christian tradition as a prophecy of the Star of Bethlehem.