Numbers 22:22
And God’s anger was kindled because he went: and the angel of the Lord stood in the way for an adversary against him. Now he was riding upon his ass, and his two servants were with him.
Cross-reference
Numbers 22:32 gives the angel's direct rebuke — continuing the same encounter and explaining why the angel opposed Balaam.
Numbers 22:35 resolves the confrontation — the angel's warning clarifies why God was angry and gives Balaam a second chance.
Exodus 4:24 shows the LORD seeking to kill Moses on his way — parallel to the angel opposing Balaam here as an adversary on a journey.
2 Peter 2:16 explicitly recalls Balaam's donkey speaking — citing this very episode as a rebuke of the prophet's madness.
In Genesis 48:16, Jacob blesses by the angel who redeemed him — contrasting with the angel who stands as adversary here.
Hosea 12:4 describes Jacob striving with an angel and winning — in contrast, Balaam here faces an angel as adversary without striving.
Exodus 3:2-6 records the angel of the LORD appearing to Moses — similar theophany but with different purpose: calling vs opposing.