Lift not up your horn on high; speak not with a stiff neck. The phrase, "a stiff neck," common in the Pentateuch (Exodus 32:9; Exodus 33:3, Exodus 33:5; Exodus 34:9; Deuteronomy 9:6, Deuteronomy 9:13; Deuteronomy 10:16; Deuteronomy 31:27), is rare elsewhere.
It expresses pride, arrogance, and obstinacy.