“An outstretched arm”
I will redeem you with an outstretched arm and with mighty acts of judgment. (Exodus 6:6 BSB)
What it sounds like today
A literal image of a long arm reaching out.
The cultural key
'With an outstretched arm' (often paired with 'a mighty hand') is a fixed Hebrew idiom for the exercise of overwhelming, decisive power, the arm being the seat of strength and the symbol of a warrior or king in action. The image was common royal propaganda in the ancient Near East, and pointedly so in Egypt, where Pharaoh was regularly depicted and praised as the god-king with the 'mighty arm' who smote his enemies. So when God says He will redeem Israel 'with an outstretched arm,' He is claiming, in Pharaoh's own royal language, the very power Pharaoh boasted of, and turning it against him: the true King will bare His arm and shatter Egypt. The phrase becomes a refrain for the exodus throughout the Old Testament. A modern reader pictures a reaching arm; the first hearers heard the language of a mighty king going to war.
Recovered meaning
'An outstretched arm' is idiom for overwhelming power in action, borrowed from royal and Egyptian imagery of the king's 'mighty arm.' God claims that power and turns it against Pharaoh to deliver Israel.