Charles Ellicott Commentary Genesis 49:18

"I have waited for thy salvation, O Jehovah." — Genesis 49:18 (ASV)

I have waited for your salvation, O Lord (Jehovah). —Among the many explanations offered for this exclamation, the most probable, as given in the Speaker’s Commentary, is that the thought of the serpent wounding his prey in the heel carried the patriarch's mind back to the fall of man and the promise made to Eve. Thus, it is a profession of faith, naturally elicited by this chain of ideas, in the advent at the proper time of the promised Deliverer, the accomplishment of which had become united in thought with the name of Jehovah.