en_tn/num/22/31.md

Then Yahweh opened Balaam's eyes, and he saw the angel of Yahweh

To "open one's eyes" is associated with being able to see. Alternate translation: "Then Yahweh gave Balaam the ability to see the angel of Yahweh" (See: rc://en/ta/man/translate/figs-metonymy)

with his drawn sword

A sword is drawn from its sheath in order to be ready to use. See how you translated this in Numbers 22:23. Alternate translation: "with his sword ready to attack" (See: rc://en/ta/man/translate/figs-explicit)

Balaam lowered his head and lay facedown

This indicates that Balaam is humbling himself before the angel. (See: rc://en/ta/man/translate/translate-symaction)