What does Genesis 49:18 mean?

Jacob has been proclaiming an oracle about the future descendants of each of his twelve sons, one after another (Genesis 49:1–2). He has just described the future of his son Dan's people (Genesis 49:16–17), and now utters this unexpected prayer that breaks the pattern of the passage. This does come at an unusual point in Jacob's speech, after seven of his twelve sons have been mentioned. However, it does not seem to divide between two distinct groups, or a change in his style.

Perhaps this is a continuation of the oracle about Dan, the tribe that would judge and vindicate the people. It's possible to interpret those remarks as a negative comment about Dan's fall into idolatry (Judges 18:27–31). Jacob may be praying for deliverance from the Lord in those times.

More likely, Jacob's sudden exclamation of waiting for the Lord's salvation is a reminder to his sons. This is probably a passionate request from the Lord to intervene in the troubled future Jacob has been describing. Salvation will only come from the Lord, not from the might of Israel's tribes. Israel (Genesis 35:10–11) will wait for the Messiah to bring ultimate deliverance through the redemption of His people (Luke 2:38).